Architectural and Engineering Feats and Facts

Newgrange - County Meath, Ireland

2007-07-04T06:40:00.002-07:00

Newgrange is one of the most notable archeological monuments in Europe. Named in Gaelic Uaimh na Gréine (Cave of the Sun), the great passage tomb stands on a low hillock beside the River Boyne in County Meath, Ireland, about 9 miles (14 kilometers) from the sea. Newgrange was built around 3150 b.c., making it as old as some of the neolithic temples on Malta and much older than the pyramids of Egypt. It is a dramatic testimony to the ancient Celts’ scientific and architectural sophistication. Its designers employed great mathematical skills to create such an uncannily accurate astronomical instrument of gargantuan scale. It forms the center of Brú na Bóinne, a region steeped in megalithic culture and ritual. Around it are more than forty prehistoric sites: standing stones, burial mounds, and other passage tombs. Irish mythology identifies Newgrange as the burial place of the high kings of Tara and the home of a preternatural race known as Tuatha de Danainn (people of the goddess Danu); other traditions are attached to the mystical place.

Newgrange is a colossal stone-and-turf tumulus, 1 acre (0.4 hectare) in area and approximately circular in plan, averaging about 280 feet (85 meters) in diameter; the top of its flattish dome is 44 feet (13.5 meters) high. The mound is surrounded by a retaining wall of white quartz and water-washed round granite boulders standing on a foundation of ninety-seven huge curbstones, many of which are decorated with incised patterns of triple and double spirals, concentric semicircles, lozenges, and zigzag lines. It has been estimated that there are some 224,000 tons (203,200 tonnes) of material in the structure. None of the stone is local: the curbstones and those used inside the tumulus were quarried about 20 miles (36 kilometers) from the site; the quartz comes from Wicklow, about 60 miles (100 kilometers) to the south; and the 1,600 granite boulders come from the Mourne Mountains, just as far to the north. All were quarried, transported, dressed, and fitted into place using only stone tools, and without the use of the wheel. The mound was encircled by about 40 widely spaced standing stones, up to 8 feet (2.4 meters) high, in a 340-foot (104-meter) ring. They were probably erected about 1,000 years later. Only twelve survive. The reconstruction as it can now be seen is based on some scholars’ interpretation of the position of the quartz layers found during excavations under the direction of Michael J. O’Kelly between 1962 and 1975.

For all its size, the mound encloses very little space. A single low passage, 3 feet (less than a meter) wide, penetrates 62 feet (19 meters) into the interior. The passage is lined with standing stones from 5 to 6.5 feet (1.5 to 2 meters) high and richly decorated with

patterns similar to those on the curbstones. There are twenty-two standing stones on one side and twenty-one on the other, supporting a corbeled roof of flat stones. Following the profile of the hill, the floor rises until the passage terminates in a cruciform chamber measuring about 21 by 17 feet (6.4 by 5.2 meters), with a 20-foot-high (6-meter) corbeled roof. Its stones are carved with grooves that prevent rainwater from entering the interior. Three low apses, their walls also carved with intricate geometric designs, open from the central space, Each contains a massive stone basin.

The entrance, crowned with a rectangular opening known as a “roof box,” and the passage are exactly designed so that, at dawn on the winter solstice, a shaft of sunlight penetrates to illuminate the central chamber and a triple spiral on one of the great basins. Of course, the tangential sunlight also vitalizes the carvings on the passage walls, bringing life in the depth of winter. The astrophysicist Thomas Ray has calculated that the architecture was not approximately oriented but amazingly accurate. Five millennia ago, as viewed from the inner chamber, the gap in the roof box would have matched almost exactly the sun’s apparent width. Ray demonstrates that the first beam would strike the exact center line of the floor in a patch of intense light about 6 feet (2 meters) long and just a few inches wide. Then in the space of twenty minutes it would broaden, narrow again, and withdraw.

Conjecture abounds about the purpose of Newgrange, although the truth is shrouded in mystery. It seems clear that it was more than a tomb. Cremated remains found on the floor originally had been placed in the basins in only two of the recesses; the center one, whose triple spiral is annually illuminated by the rays of the sun, contained no remains. Some sources suggest that it was the focus of religious rites and only occasionally used for burials; others think that its purpose changed over centuries; and still others that it was simply a giant calendar—the least acceptable of all the explanations. Archeological investigation continues. Newgrange is open to the public and the inevitable impact of large numbers of visitors—close to 200,000 a year—is endangering its ancient fabric. Although it remains as weatherproof as ever, the humidity from tourists’ breath is a growing threat that the ancient builders could never have foreseen. It is expected that access will be restricted, especially during the summer months.

Nemrud Dagi - Turkey

2007-07-04T06:40:00.001-07:00

The hierotheseion (royal burial precinct) of King Antiochos I of Kommagene (reigned ca. 69–36 b.c.) stands on Nemrud Dagi, the highest point of his domain, near the modern village of Kahta in the southeastern Turkish province of Adiyaman. It has been characterized by UNESCO as “one of the most ambitious constructions of Hellen[ist]ic times.” The megalomaniac king reshaped the 7,000-foot-high (2,150-meter) mountain by leveling the rock and filling the artificial platform with huge statues of himself and the gods (whom he claimed as kin); he then ordered a 500-foot-diameter (150-meter), 163-foot-high (50-meter) tumulus (artificial peak) of fist-sized rocks to replace the natural summit. It is believed that his tomb, yet unopened, lies beneath the massive pile of rubble.

Kommagene was a small buffer state between the Roman Empire and the kingdom of Persia. Located between the Amanos Mountains and the upper Euphrates, its capital Samosata commanded a strategic crossing of the great river. Mithradates’ father, Ptolemy, used that fact to seize control of the resource-rich area. It became an independent state in 162 b.c. After a brief subjection of the area to the Armenians, in 69 b.c. the Roman general Pompey installed Antiochos I on the throne. About 100 years later King Antiochos IV lost his wars with Rome and Vespasian absorbed Kommagene into the province of Syria.

Antiochos I attempted to establish a new order. His first action was to build a hierotheseion to his father Mithradates Kallinikos I (died 63 b.c.) in the city of Arsameia (now Eski Kale). Its decorations and inscriptions made it clear that Antiochos intended to Hellenize the Kommagenian culture, uniting die Persian Parthian world with the Greco-Roman; in effect, he set out to establish a new religion in which his own assumed divinity loomed large. Nowhere was that more evident than in his own hierotheseion on Nemrud Dagi.

The great tumulus is flanked on the east, west, and north by terraces carved from the mountain; it has been estimated that their creation involved the removal of 7 million cubic feet (200,000 cubic meters) of rock cut away by hand. On the east terrace stood an array of statues of the king and the gods, up to 33 feet (10 meters) high, carved from massive stone blocks mined in a remote quarry. The figures were set in order and identified by inscriptions written in Greek and Persian: Antiochos himself, the mother goddess Kommagene, the father god Zeus-Oromasdes (largest of the statues), Apollo-Mithras, and Herakles-Artagnes. Their faces were finely carved in the late Hellenistic style. At either end, the row of deities was guarded by the royal symbols: an eagle and a lion. At the eastern corner of the terrace stood a pyramidal altar of fire, and various elements around the platform carried carved relief portraits of the illustrious Persian and Macedonian ancestors whom Antiochos claimed as his own. Other relief decoration abounded.

As far as the topography would allow, the west terrace, set some 33 feet (10 meters) lower than the east, was organized in the same way, to much the same purpose: the apotheosis of Antiochos. The syncretized Persian and Greek gods facing east and west on the respective terraces revealed Antiochos’s attempted cultural synthesis. One inscription asserted that he had commissioned the site for posterity “as a debt of thanks to the gods and to his deified ancestors for their manifest assistance”; he wanted to set for his people an example of the piety due “towards the gods and towards ancestors.”

The north terrace, 269 feet (80 meters) long, was used for assemblies and rituals and also served as a processional way connecting the other terraces. Gigantic stone eagles flanked its entrance. The great tumulus was built on a rocky hill framed by the terraces. According to inscriptions, this was the place where Antiochos ordered that his remains should be buried. He died before his elaborate project was completed, and his son Mithradates neither finished the monumental work nor promoted the religious synthesis begun by his father. The site was

abandoned, the last of its priests probably leaving soon after a.d. 72.

Nemrud Dam was rediscovered in 1881 by one Karl Sester; an 1882–1883 German exploratory expedition followed, as well as a Turkish investigation. The findings of both groups were published, but no more research was carried out until 1938, when Germans F. Karl Dörner and Rudolf Naumann visited the site. Dörner returned after 1951 to work with the American Teresa Goell. In 1984–1985 a Turkish-German restoration team, led by Dörner, reerected the bases of the statues in their places. In 1987 the site was inscribed on UNESCO’s World Heritage List, and the following year a 35,000-acre (13,850-hectare) region around Nemrud Dagi was declared a national park. In July 1997 the Turkish government assured the world that the stone heads—all had fallen from their places—would be reset, and measures would be taken to protect the site, not only from natural damage but also from that caused by vandals or just careless tourists. Eighteen months later, the Netherlands-based International Nemrud Foundation received presidential support for a five-year master plan to restore the site, and work commenced at the end of May 2000.

Nazca Lines - Peru

2007-07-04T06:39:00.002-07:00

The Pampa Colorado (Red Plain) is a 37-mile-long (60-kilometer) and 15-mile-wide (24-kilometer) plateau in the coastal desert of southern Peru near the town of Nazca. Across its broad face are carved staggeringly cyclopean patterns, an agglomeration of designs on the earth’s surface known as geoglyphs, which portray animals, birds, and other forms, mostly made by removing the dark reddish brown surface to expose a lighter-colored substratum; in some places piled rocks define the enigmatic forms. The challenge presented to the modern imagination by this ancient engineering feat is threefold: its momentous scale and the accuracy of surveying techniques that could project straight lines for miles over irregular terrain are remarkable enough. Beyond them is the uncanny ability of a people whose entire spatial experience was planar, never far above the surface of the earth, to conceive of geometric patterns and representational images whose accuracy and intricacy could be fully appreciated only from high—indeed, very high—above.

The Nazca Lines, as they are called, comprise literally thousands of zigzag, parallel, crossed, or radiating lines: some are 6 feet (1.8 meters) wide, others just a tenth of that. Some stretch for 6 miles (10 kilometers), maintaining their straightness regardless of the uneven topography. There are also simple or complex geometric shapes, including triangles and rectangles, nearly twenty varieties of fantastic birds, a monkey, a spider, a dog, a fish, a tree, and a hummingbird represented. As to their size: the monkey occupies the area of a football stadium; one bird has a 350-foot (100-meter) wingspan; and the spider, among the smallest geoglyphs, has a diameter of 150 feet (45 meters). Together, the lines and figures cover 45 square miles (115 square kilometers). Of course, they are best seen from above and were discovered only when aircraft first crossed the area in the 1930s.

The origin of the lines remains uncertain, although because of their similarity to design motifs on other artifacts, they are attributed to the well-developed Nazca civilization, which flourished between 200 b.c. and a.d. 600. Based on the same evidence, some sources suggest that three successive cultures were responsible for the lines: the Paracas (900–200 b.c.), the Nazcas, and later settlers who migrated from Ayacucho around a.d. 630.

Each culture was agrarian and it is likely that the lines may have been associated with rituals to guarantee a rich crop. On the other hand, the German anthropologist Dr. Maria Reiche, who studied the Nazca Lines for nearly fifty years, believed that they were a vast astronomical calendar, also associated with farming. Studies in the 1980s led others to the conclusion that, while part of elaborate rituals related to fertility, the lines had neither astronomical nor calendrical significance. A decade later a new theory emerged: they charted the origins and courses of aquifers—rivers beneath the desert—associated with irrigation farming in the region. In our modern culture of scientism we disengage the rational from the spiritual, and care must be taken to avoid too simple an interpretation of the actions of people whose universe was better integrated. All of the suggestions about the purpose of the Nazca Lines could be accurate

Even in their own time and place the Nazca Lines were not an isolated phenomenon. Many geoglyphs are to be found throughout South America. Areas with lines and figures very like Nazca’s have been studied on the central Peruvian coast between the Fortaleza, Pativilca, and Rimac Valleys. Others have been found in the Viru Valley, on Peru’s north coast, and in the Zana Valley, more than 600 miles (1,000 kilometers) north of Nazca. More examples of ground figures and hill figures survive on the other side of the world. The 370-foot-long (110-meter) White Horse (ca. 500 b.c.) cut into the chalk hills at Uffington is among Britain’s most famous, second only to the pre-Christian Cerne Giant in Dorset, a 180-foot-tall (54-meter) human figure, carrying a 120-foot (36-meter) club; there is also the Long Man of Wilmington, Sussex.

As late as 1998 a 2.5-mile-tall (4-kilometer) figure of an aboriginal warrior was discovered carved on the desert floor near Marree in the South Australian outback. It was soon exposed as a hoax, created with the help of satellite tracking equipment and earthmoving machinery The very fact of the difficulty of making such a figure using modern technology emphasizes more the incredible achievement of the ancient creators of the Nazca Lines.

Mystra, Greece

2007-07-04T06:39:00.001-07:00

The ruins of the medieval city of Mystra are 3 miles (5 kilometers) northwest of modern Sparta in the Peloponnese. In 1204 the Fourth Crusade, turned aside from its original purpose by Venetian bribes, sacked Constantinople and established Frankish dominion over Greek territories. Among the most important states they founded was the Principality of the Morea, or the Principality of Achaea, governed from 1210 by Geoffroi I de Villehardouin. In 1249 his second son, Guillaume II de Villehardouin, built a castle atop a steep cone-shaped foothill overlooking the fertile valley of Eurotas and strategically commanding the Taygetos Range to the west and the valley of Laconia to the east.

Over the next few centuries the city of Mystra grew on the slopes below. Its name probably comes from the shape of the hill, which resembled a Myzethra cheese. Mystra, with a population that once exceeded 42,000, has been dubbed the “wonder of the Morea.” Like Venice, but for different reasons, it occupies a site that is totally inappropriate for a city, and its construction was a significant architectural achievement.

In 1261 the Byzantine emperor Michael VIII Palaeologus regained Constantinople. The following year, Guillaume II de Villehardouin paid his ransom—he had been captured in 1259—with a number of castles including Mystra, and Michael VIII installed a Byzantine despot. The Villehardouin line survived until 1301, when Philip of Savoy became Prince of Morea. Throughout most of the fourteenth century the principality was in the hands of the Angevin House of Naples, and then controlled by the Venetians. The Byzantines regained it through matrimonial and political alliances and in 1448 Constantine XI Paleologus, the last Byzantine emperor, was crowned at Mystra. For about 350 years after 1460 Turks and Venetians took and retook the city. In 1821 it was among the first places the Greeks liberated from their Turkish oppressors. Ironically, the demise of Mystra was brought about by the foundation of the modern town of Sparta in 1834. The first inhabitants came from the old city; others built the modern village of Mystra.

Mystra has had a tumultuous history, and the different traditions of its occupiers account for its hybridized architecture. In the mid–thirteenth century, the Byzantines’ persistent attempts to expel the Franks caused anxiety among the local populace. Many left the Eurotas plain to settle closer to the castle of Mystra. Houses were built on the lower slopes of the hill, and soon churches were constructed, clinging to the mountainside. This precipitous medieval city was surrounded by inner and outer circuit walls, commissioned in 1249 by Guillaume II de Villehardouin, and later repaired and augmented by the Byzantines and the Turks when they occupied the city. The walls were fortified by high rectangular towers, and of course dominated by the castle. They can hardly be described as concentric, because they snaked along contours and plummeted down steep slopes; nevertheless, they contained and defended the city. On its northeast and west sides the craggy hill

of Mystra climbs sheer from the narrow valley. The defensive walls divided Mystra into the lower and upper quarters: the urban classes lived in the former, while the aristocracy occupied the latter with its palaces, two- or three-story vaulted mansions, and various administrative buildings. Two heavily fortified gates—the Monembassia and the Nauplia—linked them.

The L-shaped Palace of the Despots, possibly begun by Guillaume II de Villehardouin and built in stages between the thirteenth and fifteenth centuries, occupies an incongruously flat terrace overlooking the Eurotas Valley to the east. The two wings housed many different functions: the private apartments, a palace chapel, an open colonnade, and a large well-lighted hall for assemblies and ceremonies. Just north of the palace stood the mid-fourteenth-century church of Hagia Sofia, a centrally planned funerary chapel for the despot Manouil Katakouzenos. The winding streets of Mystra, as they followed the contours of the hillside, are lined with churches, many built after the metropolitan bishop of Lacedaemonia—the medieval name for Sparta—transferred his cathedra to Mystra. Chief among them is the “mixed architectural type” cathedral: the Metropolis of St. Demetrios (ca. 1309) is a three-aisled basilica at its lower level; the fifteenth-century upper floor, consisting of a women’s gallery, is a cross-in-square roofed with five cupolas. Many churches—the thirteenth-century Church of St. Theodore, the Church of the Virgin Evangelistria, and the Peribleptos Monastery (both fourteenth century)—were purely Byzantine in form. Apart from the fifteenth-century Pantanassa Convent, which is still in use, the buildings of Mystra have been reduced to ruins, some by fire, others by being used as quarries when modern Sparta was being built. A few fine frescoes survive; many more have been destroyed.

Extensive restoration work has been undertaken over many years by the Committee for the Restoration of the Mystras Monuments and the Fifth Ephorate of Byzantine Antiquities. Mystra was inscribed on UNESCO’s World Heritage List in 1989.

Mycenae, Greece

2007-07-04T06:38:00.000-07:00

Imposing even as a ruin, Agamemnon’s city Mycenae—Homer called it “Mycenae, rich in gold”—stands on a foothill of Mount Euboea between Hagios Elias and Mount Zara near the modern village that still bears its name: Mikínai. Seat of the semilegendary Atreus, it is also rich in tragic myth. Atreus’s dynasty was cursed because he fed his brother Thyestes with his own children. His son Agamemnon sacrificed his daughter to gain fair winds to take his war fleet to Troy. When he returned, his wife Clytemnestra killed him; she in turn was killed by her son, Orestes. Except on the southeast, where a steep ravine provided natural fortification, the citadel or acropolis (high city) of Mycenae was surrounded by massive and daunting walls. Parts were of polygonal masonry, with shaped stones fitted together, and the gates were built of finely dressed ashlar. But most of the defenses were built of “cyclopean” masonry, so named because the later Greeks, unable to accept that humans could have moved such huge blocks, attributed them to the mythical giant Cyclops. The true purpose of such gigantic walls is still debated by scholars: they were certainly defensive, but some suggest they may have been employed more as a show of strength. Whatever the case, for engineering audacity and skill they challenge even our modern imaginations.

The generic term “Mycenaean” is used for the Late Bronze Age (Helladic) culture that arose on the Greek mainland around 1650 b.c. and whose powerful, militaristic city-states dominated the region from 1400 until 1100 b.c. Mycenaean navies controlled the Aegean and colonized Crete, Cyprus, the Dodecanese, northern Greece, Macedonia, Asia Minor, Sicily, and parts of Italy. Then they seem to have outgrown their resources, and despite an attempt to secure the Black Sea grain routes by annexing Troy (sometime between 1250 and 1180 b.c.), the Mycenaean culture suffered such attrition that it was easily subsumed by the migrating Dorians a century later.

From its hilltop at an elevation of about 900 feet (270 meters), the citadel of Mycenae commanded a large, fertile hinterland and the Plain of Argos extended before it; the major route between the Bay of Argos and Corinth, Thebes, and Athens to the north passed under its ramparts. There had been neolithic and early Helladic use of the site between 3000 and 2800 b.c., but the earliest significant developments took place in the seventeenth century. Indeed, most of the surviving defenses date from after 1380 b.c., built in three major stages—ca. 1350, 1250, and 1225.

The walls of Mycenae were generally between 15 and 35 feet (4.7 and 10.7 meters) high, rising in places to 56 feet (17 meters); parts of them were as much as 46 feet (14 meters) thick. The earliest circuit (ca. 1350) enclosed the megaron (palace) precinct with all its ancillary buildings. About 100 years later the walls were extended to include the main western gate and an older grave pit close to it. Another gate, much smaller but just as cunningly designed for defense, is on the north of the citadel. Around the same time, a tunnel was built in cyclopean masonry, leading to a subterranean spring-fed cistern on the northeast side.

Impressive as they are, the walls of Mycenae pale beside the splendor of the western gate, now known as the Lion Gate (ca. 1250 b.c.), mainly because of the majestic sculpture—the earliest large relief sculpture on the Greek mainland—that crowns it. The gate had a forecourt about 50 feet long by 25 feet wide (15 by 7.5 meters). The 10-foot-square (3.5-meter) opening was formed by four massive stone blocks (a threshold, flanking pilasters, and lintel), averaging about 12 by 7 by 3 feet (3.5 by 2 by 1 meters) in size. The double gates themselves were of bronze sheathed timber. The remarkable feature was above the lintel. The corbeled triangular opening (known as a “relieving triangle”) was invented by the Mycenaeans to divert the huge loads of the upper wall masonry away from the lintel and into the jambs—a major step forward in civil engineering. Here the opening was filled by a relatively thin stone panel bearing a relief carving of two lionesses flanking or adoring a column. The composition evokes many earlier relics found on Crete, and the overt symbolism born of this agrarian culture’s emphasis on fertility should not be lost on us. From the Lion Gate, a 12-foot-wide (3.6-meter) road—Homer described the “broad streets of Mycenae”—led via a terraced ramp toward the defensible entrance of the flat-roofed

megaron and its associated complex of buildings near the summit. Most of the palace has been lost.

The citadel survived an attack around 1200 b.c. only to be destroyed, possibly by invading Dorians, about a century later. The walls were not pulled down and the buildings outside, found near every Helladic acropolis, were not deserted. It seems that Mycenae was continuously occupied in some form until about 468 b.c., when the small preclassical city built on the ruins of the ancient citadel was destroyed by Argos and its population banished. The city was briefly reoccupied in the third century b.c. A new temple was built at the summit of the acropolis and the city wall repaired. There is some evidence of Roman occupation, but when the Greek traveler Pausanias visited the region around a.d. 160, he found only ruins. Serious archeological investigations began in 1841 and have continued intermittently.

Mount Rushmore - South Dakota

2007-07-04T06:37:00.002-07:00

The broad granite southeast face of 5,725-foot (1,750-meter) Mount Rushmore, neat Rapid City, South Dakota, is carved with the massive portrait heads of four U.S. presidents—George Washington, Thomas Jefferson, Abraham Lincoln, and Theodore Roosevelt. For its sheer engineering ingenuity and

ambitiousness of scale—Washington’s head is 60 feet (18 meters) high—the ensemble may be regarded as an architectural feat.

In 1923 South Dakota’s state historian Doane Robinson suggested carving giant statues in the Black Hills. Perhaps he was prompted by the knowledge that a colossal Confederate memorial had been commissioned a few years earlier for Stone Mountain, Georgia, but it is more likely that the idea was first conceived as a tourist attraction. Initially, Robinson wanted to have a cluster of tall granite outcroppings known as the Needles carved to form a procession of the Amerindian leaders and European explorers who shaped the Western frontier. Conservationists resisted the idea, and there was no public support. Nevertheless, in 1925 the financial backers of the proposed memorial approached the sculptor Gutzon Borglum, who was known to specialize in large-scale sculpture and was then rather unhappily employed on Stone Mountain.

Borglum suggested that the southeast face of Mount Rushmore would make an ideal site for a monument. He proposed to carve the heads of the four presidents beside a table inscribed with a history of the United States. Such a composition would have more than regional significance; it would commemorate “the foundation, preservation and continental expansion of the United States” and be a shrine to democracy. And behind the figures a hall of records would preserve national documents and artifacts.

President Calvin Coolidge dedicated the memorial in 1927, and Borglum began drilling. But although less than half the time was spent on actual carving, the work would take fourteen years to complete. Most of the delay was due to money shortages during the Great Depression. Borglum lobbied at every political level, playing on nationalistic feelings and stressing that public works created jobs and won votes. As a result of his persistence, nearly 85 percent of the monument’s $1 million cost came from federal coffers. The Washington head, 500 feet (150 meters) up the mountain, was formally dedicated in 1930, when the name “Shrine of Democracy” was officially adopted; Jefferson followed in 1936, Lincoln in 1937, and Roosevelt in 1939. Borglum died in March 1941 and his son Lincoln supervised the completion of the sculpture.

Borglum’s plaster maquettes were based on life masks, images, and descriptions, but the differences between them and the finished heads demonstrate that the sculptor did not simply transpose from plaster to stone. Once the dimensions were scaled up to the finished size and marked out on the mountain, the team of carvers was faced with the problem of removing the unwanted granite. Despite Borglum’s first inclination against its use, dynamite was the only practical way to do that. Once an oval-shaped mass of rock was formed for each head, explosive experts blasted its surfaces to the approximate final measurements. Carvers suspended in bosuns’ chairs shaped the features. They used pneumatic drills to cut closely spaced holes that nearly defined the final surface, and the honeycombed granite was ultimately chiseled away to expose the smooth surfaces of the presidents’ faces. Viewed from a distance, stone miraculously became flesh; as the architect Frank Lloyd Wright observed, “The noble countenances emerge from Rushmore as though the spirit of the mountain heard a human plan and itself became a human countenance.”

A similar feat, already mentioned, deserves a little more detail. The north face of Stone Mountain, 16 miles (26 kilometers) east of Atlanta, Georgia, is carved with a 138-foot (42-meter) equestrian bas-relief of the Confederate heroes Robert E. Lee, Stonewall Jackson, and Jefferson B. Davis. What began in 1915 as a commission for Borglum to produce a 70-foot (21-meter) statue of Lee developed into a proposal for the group portrait. Preliminary work started soon after World War I and carving began in June 1923. Irreconcilable differences with the client caused Borglum to quit in March 1925—just as he received the Black Hills commission—when little more than Lee’s head had been finished. Augustus Lukeman replaced Borglum, dynamited most of the earlier work, and started again. Disputes over property ownership halted the project in 1928, and it was not revived until 1960, when an international competition led to the appointment of Walker Hancock as chief carver. He started work in 1964, making only slight modifications to the Lukeman design. The use of thermo-jet torches allowed for rapid, accurate removal of the stone and, in collaboration with Roy

Faulkner, Hancock had the gigantic memorial finished by 1972.

The grandiose neoclassical character and the gigantic size of Mount Rushmore and similar projects call for comment about our seemingly irresistible need to enshrine ideals that are anything but inhuman through overwhelming and inhuman scale. Consider, for example, the 150-foot (45-meter) Statue of Liberty or the Cristo Redentore above Rio de Janeiro. On the other hand, colossi have been built for reasons of vainglory: the Colossus of Rhodes collapsed after one generation; the 120-foot (36-meter) statue of Nero (originally near the Roman Colosseum and providing its name) is long gone. One of the multitude of Egypt’s Ramessean statues is described by the poet Percy Shelley as a colossal wreck, “two vast and trunkless legs of stone.” Destroyed by nature or by conquerors, such works are at once monuments to our engineering ingenuity and our transience.

Mont-Saint-Michel - Normandy, France

2007-07-04T06:37:00.001-07:00

Mont-Saint-Michel is a craggy, conical island, about half a mile (0.8 kilometer) across and standing half a mile from shore in the Gulf of Saint-Malo, near the border of Brittany and Normandy on France’s northern coast. The north side of the island is wooded and the west presents a barren face to the sea. A fortified village of fewer than 100 inhabitants huddles on the lower southern and eastern slopes and the great Benedictine abbey, dating from the thirteenth century, crowns the entire mount, towering about 240 feet (73 meters) above. The integration of monastery with village and both with the rock was noted by UNESCO as “an unequalled ensemble” when the site was inscribed on the World Heritage List in 1979. Mont-Saint-Michel is an architectural feat for that reason and others: the audacity displayed by the builders on so difficult a site and the harmony achieved between its parts, which were built in many architectural styles over five centuries.

The place known as Mont Tombe, which became Mont-Saint-Michel, has a spiritual history dating from pre-Christian times. There the Gauls had worshiped Belenus, the god of light, and there the Romans consecrated a shrine to Jupiter. By the fifth century a.d. the secluded crag and the Scissy Forest around it had become a retreat for hermits. There is a tradition that in 708 St. Michael appeared to Aubert, twelfth bishop of Avranches, directing him to build a sanctuary to the archangel on the mount. In October of the following year, Aubert consecrated a simple circular oratory, to accommodate about 100 people, and built cells to replace the earlier huts, but not before an abnormal tide—some sources say a tidal wave—had gouged a channel between rock and shore, creating the islet. At low tide a land bridge connects to the mainland across beaches of gray silt; at high tide it is covered by about 40 feet (14 meters) of water.

Under the sponsorship of Richard the Fearless, Duke of Normandy, Abbot Mainard occupied the island in 966 with twelve Benedictine monks from Monte Cassino. He built a rectangular chapel with 6.5-foot-thick (2-meter) stone walls on the ruins of the oratory. By that time, the Benedictines had enjoyed four centuries of prominence in western Europe and monasticism had reached a zenith. In France, the abbeys—there were about 120 of them— exercised great influence in many spheres: spiritual, artistic, intellectual, economic, and political. Besides the Benedictines, whose other Normandy houses were at Fecamp, Lessay, and Lonlay, the Premonstratensian (Canons had established themselves at Ardenne and La Lucerne. Eventually, Mont-Saint-Michel would become a magnet for thousands of the faithful from all over Europe.

The next building phase was initiated by Abbot Hildebert II in 1017. An extensive masonry foundation

leveled the entire top of the island and an abbey church was built on the summit. Mainard’s sturdy chapel formed its crypt and was later named Notre-Dame-sous-Terre (Our Lady Underground). The rest of the new cruciform church—with its seven bays, the nave was nearly 230 feet (70 meters) long—was supported on masonry walls and piers. The project, designed in the latest style (now known as Romanesque), was completed by 1135. That was not the end of the architectural development, and about thirty-five years later Abbot Robert de Torigny commissioned a new west front with twin towers.

In 1203 the French king Philip II Augustus sent an expeditionary force against the abbey, and some of its dependencies were destroyed by fire. To compensate for the damage, a generous endowment allowed Abbot Jordan to immediately commence the granite conventual building known as La Merveille (the Marvel), flanking the church on the seaward side of the rock. Remarkably, the extensive, logistically

difficult works were completed by 1228. The Marvel began at 160 feet (49 meters) above the sea and consisted of three terraced levels. The lowest housed the almonry and cellar. The second was taken up by the kitchens; a huge refectory with timber barrel vaults; a guest hall, adorned with tapestries, stained glass, and glazed tiles; and a scriptorium (now called the “hall of the knights”). At the top was the monks’ dormitory and a beautiful arcaded, vaulted cloister attributed to Raoul de Villedieu.

In contrast to that tranquil security, the Marvel has been described as “half military, half monastic.” Louis IX visited the Mont in 1254 and later helped to pay for its fortification. Strategically located, it acquired a defensive role and housed a garrison jointly paid by king and abbot. Through the fourteenth and fifteenth centuries, both the abbey and the town were enclosed by walls on the land side, adding another texture to the varied architecture of the rock. Frequently attacked, it would never be captured, even remaining unconquered when English armies took most of the fortresses of Normandy early in the fifteenth century.

There was a series of structural failures in the abbey church. In 1300, one of de Torigny’s west towers fell down. More serious was the collapse in 1421 of Hildebert’s Romanesque choir. France was still at war with England, and all thought of reconstruction was deferred until 1446, when a massive base known as the Crypt of the Large Pillars was built as foundation for a replacement building. Work on the new choir began in 1450 and it was completed in 1521. Apsidal in plan, with radiating chevet chapels, it was naturally built in the contemporary, highly ornate French style, appropriately named flamboyant because of the flamelike patterns of its window tracery. Other architectural failures followed: in 1618 the de Toringy west facade started to collapse, and eventually it was pulled down in 1776, together with, the three western bays of the nave.

The monastic foundation seemed to decline with the buildings. Although by the twelfth century under de Toringy, the Benedictine abbey of Mont-Saint-Michel had acquired fame for its intellectual life, drawing pilgrims from across Europe, about a century later its power had begun to slowly wane. As the balance of its role tipped from devotion to defense, the size of the community decreased. In 1523 it was granted in commendam to Cardinal Le Veneur, the series of commendatory abbots continuing until 1622—by then hardly any monks remained—when control passed to the reformed congregation of St. Maur. In turn, the Maurist monks were dispossessed during the French Revolution. From 1790 the abbey, its name ironically changed to Mont Libre (Mount Freedom), was used to incarcerate criminals and political prisoners. Napoléon III abolished the prison in 1863. Having gone full circle, the buildings were leased to the Bishop of Avranches until 1874, when the Commission des Monuments Historiques appointed the architect E. E. Viollet-le-Duc to restore it. In 1966, in recognition of the monastery’s millennium, the French government allowed the resumption of monastic life on Mont-Saint-Michel; since then a community of monks, nuns, and lay oblates lives in a part of the abbey, reviving the ministry to pilgrims.

This has been a complicated story, whose point is just this: the architectural feat of Mont-Saint-Michel was not achieved in a day, a month, or a year. The harmony and the unity of its parts, diverse in date, style, and function, took 500 years to realize.

Mohenjo-Daro - Pakistan

2007-07-04T06:36:00.002-07:00

The city of Mohenjo-Daro (“hill of the dead”) was the largest settlement of a culture that for more than 600 years from 2500 b.c. extended over 600,000 square miles (1.5 million square kilometers) of India and Pakistan—larger than western Europe. The city’s ruins, on the west bank of the Indus River about 200 miles (320 kilometers) north of Karachi, evidence careful urban design combined with a sophisticated infrastructure that was undreamed of in the contemporary river-valley civilizations of Egypt and Mesopotamia. Although presented with undeniably nationalistic and political bias, recent archeological evidence from the subcontinent suggests that there, and not in Mesopotamia, was the cradle of civilization. Mohenjo-Daro has been chosen here as simply representative of a great achievement, the invention of city planning.

The first traces of the ancient cities were accidentally discovered on the Indus River floodplain in 1856. The occupying British, building the East Indian Railway between Lahore and Karachi, plundered hundreds of thousands of bricks from the site of Harappâ, a metropolis on the Ravi River, 400 miles (640 kilometers) northeast of Mohenjo-Daro. In 1920 Sir John Marshall, director general of archeology in India, initiated investigation of these “twin capitals,” and discoveries were made by Daya Ram Sahni (at Harappâ) and R. D. Banerji. Nani Gopal Majumdar worked in the Sindh region (now in southern Pakistan) from 1927 to 1931. About a decade later, Ernest Mackay discovered Chanu Daro, and Sir Aurel Stein found more sites in Baluchistan and Rajputana. From 1946 into the early 1950s, Sir Mortimer Wheeler continued excavations at Mohenjo-Daro and Harappâ.

The terms “Indus valley civilization” and “Harappân culture” spring from the collective work of all these men, but Hindu scholars in India and Pakistan recently have challenged that nomenclature. Some insist that the civilization was created by Vedic people. Hard evidence is displacing earlier speculative myths about origins. Since the early 1990s archeologists have uncovered several cities east of the Indus. The settlement known as the Dholavira

excavation, about 150 miles (250 kilometers) from modern Bhujin in India; another under modern Rakhigarhi in the Haryana district; and Kunal, also in Haryana and close to the dry Ghaggar-Hakra River (thought to be Mother Saraswati of the Rig Veda), are evidence of how widespread Harappân culture was. It extended from the mountains of northern Afghanistan south to the Arabian Sea, and from the Baluchistan highlands in the west eastward to the Thar Desert, once a fertile plain watered by the Saraswati. Of about 1,400 sites now uncovered, about 900 are in India, 1 is in Afghanistan, and the remainder are in Pakistan. Because there are more Harappân settlements along the Saraswati than along the Indus, it has been suggested by some Indian archeologists that the name “Indus-Saraswati” civilization be adopted; their peers in Pakistan prefer “Hakra” civilization.

However modern scholars choose to classify them, well-structured barley- and wheat-growing communities existed in the region around 4300 b.c., and by 3200 b.c. large villages stood along the great rivers. The historian Arnold Toynbee has suggested that such locations were chosen not because they offered an easy life but because of the challenges presented by annual flooding. Whatever the case, the Harappâns made a dizzying leap from villages to cities between 2600 and 2500 b.c. As elsewhere, there was no intermediate, evolutionary step. The U.S. archeologist Gregory Possehl describes this as a century of cathartic changes, and Gordon Childe coined the expression “the urban implosion.” Quite suddenly, there existed commercial centers with high levels of municipal control; complex social organization; specialized occupational structures; administrative expertise; and tools, such as a system of writing (that of the Indus-Saraswati culture is as yet undeciphered), mathematics and especially geometry, survey instruments, and standard weights and measures.

Although there were other locations of comparable size and importance, Mohenjo-Daro was certainly a principal—and typical—city. This largest Indus valley settlement covered more than 200 acres (80 hectares) and was over 3 miles (5 kilometers) around. Like most Indus-Saraswati cities, it had two principal and functionally disparate districts, each built on a huge mud-brick platform, which raised it above the annual floods. To the west stood the 45-foot-high (14-meter) “citadel,” measuring 1,400 feet (430 meters) by 450 feet (140 meters). Fortifications have survived at its southeast corner and the entire platform may have been enclosed by a wall. Several public buildings stood on it. Archeologists once imagined these to include a large granary (with a wooden superstructure), an assembly hall, a college, and a ritual tank, but more recent scholarship has found no evidence for those conclusions. Whatever their purpose, the layout and juxtaposition of the structures demonstrates careful urban design. Noteworthy among the buildings was the so-called Great Bath, about 29 by 23 feet (8.8 by 7 meters) and 8 feet (2.4 meters) deep, entered by steps at each end. It was built of fired bricks laid in gypsum mortar and sealed with bitumen.

Across an area of probably unused land, the residential “lower” city of Mohenjo-Daro occupied a more extensive platform to the east. It also was set out on a north-south, east-west grid of properly drained, brick-paved streets, 30 feet (9 meters) wide, forming rectangular urban blocks measuring about 400 by 270 yards (360 by 240 meters). Tightly packed courtyard houses and places of business, all built of fired brick, faced the streets. It is likely that internal walls were plastered, and most houses had stairs leading to either a second story or a flat roof. The houses normally had a private bathing area supplied with water from their own wells, and a properly drained toilet. A secondary grid of narrow service lanes subdivided the main blocks, and chutes from most residences were connected to a system of covered sewers—more evidence of well-developed municipal controls that still cannot be found in many Asian cities. Because of the high water table beneath Mohenjo-Daro, it is impossible to extend archeological investigation to its foundation level. Exploration continues, and in the early 1980s German scholars discovered a “suburb” about 1 mile (1.6 kilometers) from the “downtown area.”

Harappâ and many other Indus-Saraswati sites are almost identical to Mohenjo-Daro in layout and organization, indicating that, at the peak of the civilization, regional centers may have been built to a

standard city plan. There are exceptions in detail, if not in overall form.

This remarkable civilization remained unified for nearly 700 years. Then, partly because of overexpansion of its trade networks, after about 1900 b.c. it gradually disintegrated into a regionalized pattern of cultures, referred to as late or post-Harappân. Within 150 years Mohenjo-Daro’s efficient urban government had deteriorated. Administrative breakdown was augmented by ecological factors. Recent research has established that most protohistoric cultures suffered three centuries of persistent drought from about 2200 b.c., perhaps activated by a sudden global climate change. The passing of the Indus-Saraswati cities can be attributed in part to changing river patterns, upsetting a river-based agricultural and trade economy that had already outgrown its strength. The Saraswati dried up, the Hakra-Nara’s tributaries were diverted eastward to the Jamuna River and westward to the Indus, and the course of the Indus itself began to change, resulting in frequent violent flooding of its southern reaches.

Moai monoliths

2007-07-04T06:36:00.001-07:00

The small Pacific island of Rapa Nui (Easter Island), 2,300 miles (3,680 kilometers) west of Chile, is the most remote inhabited island in the world, with Pitcairn, its nearest neighbor, 1,400 miles (2,240 kilometers) away. The staggering architectural

achievement of the people of Rapa Nui was the creation, but especially the transportation and erection, of hundreds of monolithic moai—stylized giant human heads-on-torsos—carved in hardened volcanic tufa. On average, the statues are 13 feet (4 meters) high and weigh 14 tons (14.22 tonnes). But the largest ever raised once stood at the prominence known as Ahu Te Pito Kura; nearly 33 feet (9.80 meters) high, it weighed about 91 tons (83 tonnes). Even it would have been dwarfed by another found incomplete in a quarry: measuring almost 72 feet (21.6 meters), its weight was perhaps 185 tons (168 tonnes).

Since the Dutch seafarer Jacob Roggeveen made Rapa Nui known to Europe in the 1720s, scholars have debated the origins of its culture. Local legend has it that the canoes of Hotu Matu’a (the Great Father) arrived from Polynesia around a.d. 400. Some scholars, citing archeological evidence, assert that they came between 300 and 400 years later. Whatever the case, among the lush palm forests the newcomers planted their gardens of bananas, taros, and sweet potatoes. The South American origin of the latter led the adventurer Thor Heyerdahl to conjecture that Polynesia had been colonized by pre-Inka people, a view refuted by later scholars, who cite biological, linguistic, and archeological evidence to support Southeast Asian origins. As compelling as it is, the question is not our present concern.

Unique in Polynesia, the mysterious moai are thought to have been carved between a.d. 1400 and 1600 by specialist master craftsmen using tools made from obsidian found at Orito. The figures, always male, are believed to be iconographic representations of powerful beings—ancestors, chiefs, or others of high rank—rather than portraits. The red volcanic stone for their headdresses (pukaos) came from the Puna Punau volcanic crater; their eyes were made of shell and coral. They were the product of a spiritual and cultural imperative that seems to have become an obsession.

The archeologist Jo Anne van Tilburg of the University of California at Los Angeles suggests that the statues acted as ceremonial mediators “between sky and earth, people and chiefs, and chiefs and gods.” The statues were transported, probably by conscripted labor, from where they were quarried and set up on the perimeter of the island, mostly on the southeast coast. Some were moved up to 14 miles (22.4 kilometers) and placed facing inland upon flat mounds or stone pedestals (ahu) about 4 feet (1.2 meters) above the surrounding ground. The word ahu also conveys a sacred site, and some, comprising massive masonry blocks and tons of fill, supported a whole group of moai.

For fifteen years van Tilburg carried out a “census” of the moai, finding a total of 887 statues. Fewer than one-third (288) had been transported to their coastal locations. She recorded another ninety-two as “in transport,” that is, on their way to their intended locations. The remainder were still in the quarries at what van Tilburg calls the central production center, in the volcanic caldera known as Rano Raraku near the eastern end of Rapa Nui. Perhaps they were abandoned because flaws were found in the stone, perhaps they were too large to move, or perhaps deteriorating social conditions forced the work to end.

How were they moved to their solemn stations around the coast of Rapa Nui? Several possibilities have been suggested. There is a local tradition that the moai “walked” to their sites, which led Heyerdahl to conclude that they were stood upright and rocked from side to side, thus “walked” along. A poorly rendered Dutch illustration of 1728, showing a statue standing upright on a base at which people are working, has been interpreted as moving the moai on rollers. Both systems have been tested using pseudo-moai and both worked. Others have suggested that the gigantic figures were laid prone, just as they had been carved, and dragged on sleds. Working from computer models that took account of many variables, including the food needed for the workers, van Tilburg proposed a plausible alternative, tested by experiment: the massive figures were moved in the prone position, supported on long logs that were rolled on smaller ones. In fact, no one knows with certainty how such loads were moved over the difficult terrain of the island.

Around a.d. 1550, Rapa Nui’s population reached a peak of about 10,000, placing an untenable load

on the tiny island’s resources just when moai carving and, more significantly, transportation reached a climax. Over the next century or so, radical change occurred, heralding the collapse of the society. Some scholars lay most of the blame for decline on the compulsion to construct the colossal figures. The once abundant palm forests were cleared for housing and crop production and to provide tools and pathways for moving the moai. Deforestation allowed the erosion of topsoil, and crops failed. Soon, driven by territorial imperatives, the island clans descended into civil war and even cannibalism. All the coastal moai had their eyes smashed out and the statues were toppled and decapitated by the islanders themselves.

Contacts with the West from the beginning of the eighteenth century served only to make matters worse, and in 1862 Peruvian slavers and exotic diseases together ravaged the population, reducing it to little more than a hundred. The process was reversed after Rapa Nui was annexed by Chile in 1888, and in 1965 it received the same privileges as other Chilean provinces. The economy now depends on sheep ranching and tourism. The main attraction for tourists is the mysterious moai, whose uniqueness led to the island being inscribed on UNESCO’s World Heritage List in 1995, with the following description:

Rapa Nui … bears witness to a unique cultural phenomenon. A society of Polynesian origin … established a powerful, imaginative and original tradition of monumental sculpture and architecture, free from any external influence. From the tenth to the sixteenth centuries this society built shrines and erected enormous stone figures, moai, which created an unrivalled cultural landscape and which today continue to fascinate the entire world.

Mishkan Ohel Haeduth (the Tent of Witness)

2007-07-04T06:35:00.003-07:00

The Mishkan, or sacred tent, was a unique portable temple constructed under the direction of Moses as a place of worship for the Hebrew tribes. It was used during the forty-year period of wandering between their liberation from slavery in Egypt and their arrival in the Promised Land (ca. 1290–1250 b.c.). According to chapters 25 and 26 of Exodus, the warrant and exact specifications for its construction were given by God. The tent seems to have been still in use in the first half of the eleventh century b.c., but it no longer served a religious purpose after Solomon built a permanent temple in Jerusalem in 950 b.c.

Portable shrines existed in Egypt as early as the Old Kingdom (2800–2250 b.c.), and fine examples were discovered in the tomb of Tutankhamen, (ca. 1350 b.c.). But they are small in comparison with the Tent of Witness, which differed from all contemporary religious buildings in several remarkable ways. First, it was the only temple constructed by the monotheistic Israelites, in contrast to the many—often several dedicated to the same deity—built by their polytheistic neighbors. Second, it was never associated with one particular sacred geographical location, peculiar to the deity; rather, it was set up wherever Yahweh, the God of Israel, indicated, in the belief that his presence made every location sacred. Third, it was small and outwardly unimposing,

and although constructed of the choicest durable materials, it did not have (indeed, could not have) the appearance of weighty permanence common to contemporary religious buildings. Fourth, the materials used imparted a brightness that contrasted with the dark tents of the tribespeople who camped around it and that marked it out against the somberness of other shrines. Finally, its construction was not financed by temple taxes but by the voluntary offerings of the Israelites: according to Exodus, they gave 2,800 pounds (1,270 kilograms) of gold, 9,600 pounds (4,360 kilograms) of silver, and 6,700 pounds (3,050 kilograms) of bronze besides the necessary yarn and textiles. Its architectural character was inextricably linked to the Hebrews’ nomadic life for the first forty years of its existence. The Law of Moses provided instructions for the Levite families of Gershon, Kohath, and Merari responsible for assembling, demounting, and carrying the Mishkan and its court.

The complex invariably stood at the very center of the Israelite camp. It comprised a large courtyard around a comparatively small building that may be regarded as the Tent of Witness proper. The outer court was enclosed by a white linen wall, 150 feet (46 meters) long by 75 feet (23 meters) wide and 7.5 feet (2.3 meters) high, hung on 60 pillars of the brownish orange wood from the durable desert acacia. The pillars, each crowned with a silver capital, stood on bronze sockets, and their guy ropes were fastened with bronze pins. Access to the court was through a “gate” at the eastern end, also of white linen but distinguished from the general walls by an embroidered pattern in blue, purple, and scarlet and fastened to its pillars with gold hooks. Immediately inside the gate was an altar made of bronze-sheathed acacia wood. It is a comment upon the portability of the sanctuary that, at only 7.5 feet (2.3 meters) square and 4.5 feet (1.35 meters) high, this was the largest of the furnishings, designed to be carried on poles, rather like a sedan chair. Nearby stood a bronze basin holding water used for the priests’ ritual ablution.

The Tent of Witness itself stood at the western end of the court. An oblong enclosure, about 45 feet long by 15 feet wide (13.5 by 4.5 meters) and 15 feet high, was framed by walls assembled from 48 gold-sheathed acacia boards, each 27 inches (about 70 centimeters) wide. Standing on foundation blocks of solid silver, the boards were locked together by a system of bars passed through brackets on their outer faces and through their centers.

The plain exterior gave no clue to the richness and brilliant color of the rooms it contained. The ceiling was a draped curtain of the same textile as the courtyard gate, covered with another of goat’s hair, then red-dyed rams’ skins; an outer layer of porpoise skins provided durable protection. The interior was reached through a door of the same embroidered fabric hung on gold-sheathed pillars. By absolute contrast, the floor was simply the earth of the desert. The first compartment, 30 by 15 feet (9 by 4.5 meters), was called the Holy Place. It was furnished with a gold-sheathed table; a small altar for burning incense, also covered in gold; and a seven-branched menorah (lamp stand) hammered from solid gold. Beyond an inner curtain emblazoned with embroidered cherubim (angelic beings) was the Holy of Holies. The only furniture in that inner sanctum was the Ark of the Covenant, a gold-sheathed wooden box containing the stone tablets of the Ten Commandments. This was the dwelling place of the God of Israel, who sat invisibly enthroned above the gold “seat of atonement” that rested on the Ark. Access was denied to all except the High Priest, and then only on Yom Kippur (the Day of Atonement). Because of the uniqueness of the spiritual beliefs that the Tent of Witness expressed, it was never a prototype for anything else. When Solomon built the great temple in Jerusalem, the architectural emphases were quite different.

Mir space station

2007-07-04T06:35:00.001-07:00

Mir (Russian for “peace”) was conceived in 1976 as the climax of the (then) Soviet program to achieve the long-duration presence of a man in space. Its first component was launched into orbit ten years later. The first modular station assembled in space, it is the pioneer work of extraterrestrial building; constructed in a virtually gravity-free environment, it is unique among architectural and engineering works. Earlier space stations had been integral units, completed before launching. Mir circled the earth for over fifteen years. As first proposed, it was 43 feet (13.1 meters) long and 13.6 feet (4.2 meters) in diameter; its mass was 46,200 pounds (20,900 kilograms). By 1985 the Russian Space Agency had decided that four to six additional modules, each with a mass of 46,000 pounds (20,800 kilograms), would be moored at docking ports on the station. By the time the final module was in place, the total mass was about 221,000 pounds (100,000 kilograms). Mir, humanity’s first landmark—if that is the correct word—in space, orbited the earth at an altitude of 225 miles (390 kilometers) and an inclination of 51.6 degrees.

The primary function of the station was as a location for scientific experiments, especially in the areas of astrophysics, biology, biotechnology, medicine, and space technology. At various times, Mir was “leased” as a laboratory. Cosmonauts, astronauts, and scientists of many nationalities—Russian, American, Afghan, British, Canadian, German, Japanese, and Syrian among them—conducted over 20,000 experimental programs on board. However, space-watcher David Harland observed that Mir was the first station

to be permanently manned, extending the time spent in space for periods between one month and six; “learning how the technology degrades, and how to repair it, and do so in space” showed its real mission as a technology demonstrator.

The Mir module, the core of the station, was launched on 20 February 1986. Most of it was occupied by the main habitable section—crews’ quarters, a galley, a “bathroom” with shower, hand basin, and toilet—and the operational section, forward of which were the primary docking module and air lock. The galley was furnished with a folding table with built-in food heaters and refuse storage. For privacy, each crew member had a separate cubicle containing a folding chair, sleeping bag, mirror, and porthole. To provide a familiar environment in microgravity, the living quarters had identifiable surfaces: the floor, above several storage compartments, was carpeted in dark green; the light green walls had handrails and devices for securing articles; and the white ceiling had fluorescent lights. The other part of the core module was the station’s control area, set up for flight control, as well as systems and medical monitoring. There were six docking ports on the core’s transfer compartment for secondary modules or the Soyuz and Progress-M transport vehicles: one on the long axis, four along the radius, and another aft, connected to the working module by a 6-foot-diameter (1.8-meter) pressurized tunnel. The engine and fuel tanks were in the assembly compartment.

Five more modules, added between 1987 and 1996, completed the space station. The first, located on the aft docking port, was the astrophysics module known as Kvant-1. Nineteen feet (5.8 meters) long and 14 feet (4.3 meters) in diameter, it contained a pressurized laboratory compartment and a store. Kvant-2, about twice as long as Kvant-1, was the scientific and air-lock module added in 1989 that allowed cosmonauts to work outside the station. It also included a life-support system and water supply. Kristall, a 39-foot-long (12-meter) technological module, was attached to the station in 1990; it carried two solar arrays as well as electrical energy supply, environmental control, motion control, and thermal control systems. In 1995 U.S. astronauts installed a special docking port that allowed the U.S. space shuttle to dock without obstructing the solar arrays. Also in 1995, the Spektr remote-sensing payload arrived at Mir with equipment for surface studies and atmospheric research and four more solar arrays. Mir was completed when the Priroda remote-sensing module arrived on 26 April 1996.

The station could not remain in orbit indefinitely, and two options for closure were available. Mir could be fitted with booster rockets and moved to a higher orbit or simply abandoned and allowed to crash into the ocean. Mir fell into an uninhabited part of the South Pacific late in March 2001. That course of action was chosen so that efforts could be refocused on the construction of the International Space Station (ISS). The decision fits in with the claim of NASA (the National Aeronautics and Space Administration) that the nine U.S. collaborations with Mir since 1994 formed Phase One of the joint construction and operation of the ISS.

The ISS is a joint venture of the United States, Russia, Belgium, Britain, Canada, Denmark, France, Germany, Italy, Japan, the Netherlands, Norway, Spain, Sweden, Switzerland, and Brazil. The first components of the station, the Zarya and Unity modules, were put into Earth orbit in November and December 1998, respectively. Scheduled for completion in 2004 after a total of 44 launches deliver over 100 components, the ISS will have a mass of 1 million pounds (454,500 kilograms) and measure 356 by 290 by 143 feet (109 by 88 by 44 meters). It will orbit Earth at about the same altitude and inclination as its predecessor. A crew of up to seven will have pressurized living and working space about twice as big as the passenger cabin of a jumbo jet. Mir was there first.

Meteora, Greece

2007-07-04T06:34:00.002-07:00

The almost flat valley of the Pineios River, north of the town of Kalambaka in Thessaly, is punctuated by spectacular formations of iron gray conglomerate rock, huge, sheer-sided columns abruptly projecting up to 2,000 feet (600 meters) above the plains. On the seemingly inaccessible pinnacles of many of these weathered outcrops there stand, as though growing out of the rock, the monasteries of Meteora. Were they architectural feats? We believe so. Although most conventual buildings by definition demonstrate some degree of preoccupation with solitude, those at Meteora are unique, built where it appears virtually impossible to build. Not only were there no materials in situ, the task of delivering the imported materials to the builders—indeed, of getting the builders themselves to the precarious sites—could hardly have been more difficult. The logistical problems were subordinated to the need for isolation.

Christian monasticism originated in Egypt and spread throughout the Byzantine Empire between the fourth and seventh centuries. For a hundred years after the accession of Emperor Leo III in a.d. 717, the Iconoclasts attacked the eastern monasteries, seizing their treasured relics, thus greatly diminishing their wealth and power. As the rabid movement waned, Christian ascetics, perhaps moved with fear of a recurrence or perhaps with an eye on the restless power of Islam, sought secure places in which to follow their religious exercises. Throughout the ninth century hermits settled in rock crevices and caves in the great brooding pillars of the Pineian valley, long known as a retreat by mystics of pre-Christian religions.

As their numbers increased, the Thebaid of Stagoi Monastery was created at Doupiani, and its community grew during the eleventh century. Meteora

became a sanctuary, especially after about 1300, when it provided asylum for secular as well as religious refugees under Ottoman rule. Around 1356 St. Athanassios Meteoritis founded Great Meteoron (from which the region derives its name), and about eighty years later the Serbian Orthodox prince John Uresis joined the community, endowing it with such wealth and privilege that it soon became the region’s dominant monastic house. The growth of other foundations—Varlaam, commenced in 1350 and rebuilt in 1518; Holy Trinity of around 1470; and Roussanou, established in 1288 and rebuilt sometime before 1545—led to a golden age of monastic life and produced an environment in which scholarship and Byzantine ecclesiastical art flourished. At its peak the whole community numbered thirteen coenobite monasteries and about twenty smaller foundations. The patriarch Jeremias I (ruled 1522–1545) raised several of them to the rank of imperial stavropegion.

The monks set out to create places of inaccessible isolation. In the completed buildings entry could be gained only by a series of vertical wooden ladders of dizzying length (65–130 feet, 20–40 meters), which could be drawn up at night or when intrusion was imminent, or by nets hauled up by windlasses housed in cantilevered towers. Great Meteoron, or the Monastery of the Transfiguration, largest and highest of the houses, stands on the Platylithos (Broad Rock) 1,780 feet (534 meters) above the valley. Varlaam was originally reached by using scaffolding dug into the rock, and its windlass and rope in the tower (built 1536) were used for materials and supplies until 1963. Roussanou is built on a site only just large enough for it, and its walls stand right at the edge of the precipice. Whatever the reason for such a defense against the world—whether to protect the souls and minds of the monks or the wealth of the monasteries—the construction of these buildings in the sky, some of which are large and complex, represents a formidable challenge to the resolve and skill of the builders. It has been well met.

The monasteries generally declined in the seventeenth century (although some had failed long before), and by about 1800 they were little more than a “decaying curiosity,” a unique sight for tourists. They surrendered their independence to the Bishop of Trikkala in 1899. At the beginning of the twenty-first century only five are still occupied: the monasteries of Great Meteoron, Ayia Triadha, Varlaam, and the convents of Agios Stefanos and Roussanou

Mesa Verde Cliff Palace - Colorado

2007-07-04T06:34:00.001-07:00

Mesa Verde National Park is spread over more than 52,000 acres (21,000 hectares) of a well-wooded mesa between Cortez and Durango, Colorado, at a general elevation of 7,000 feet (2,100 meters). Within its boundaries are the ruins of almost 4,000 Amerindian settlements, some up to 1,300 years old. The largest and most remarkable is the so-called Cliff Palace, a multistory building like a modern apartment block built under overhanging cliffs. It accommodated probably 100–150 people in its 151 rooms and 23 kivas, and its size and complexity make it a preeminent feat of “architecture without architects.”

Who were these exceptional builders? They are generally known as the Anasazi (Navajo for “ancient ones”), and their civilization was centered around the region where the states of Arizona, New Mexico,

Colorado, and Utah now join. Some scholars identify the Anasazi as the ancestors of the Hopi and other indigenous Pueblo groups of the southwest United States, and modern Pueblo Indians prefer to call them “ancestral Puebloans.” The precise origins of the Cliff Palace dwellers are unknown: certainly there were permanent settlers in the region before a.d. 500, farming and using caves or adobe structures for shelter and digging covered storage pits. By about 700 villages were being built: those in caves consisted of half-buried pit houses, while those on open ground had straight or crescent-shaped row houses with rooms both above and below ground. For the next three centuries the same house types—though somewhat larger—persisted, and stone masonry began to replace earlier pole-and-mud construction. The pit houses are the predecessors of the kivas, underground chambers common in the next phase of building.

Known as the Classic Pueblo period (a.d. 1050–1300), this was the era of the Cliff Palace and other villages built in similar sheltered depressions, as well as large freestanding apartment-like structures along the walls of canyons or mesas. Most consisted of two to four stories, differing little in construction from the earlier masonry and adobe houses, and often stepped back so that lower roofs formed a sort of patio reached from the floor above. All were built in places difficult to reach, some accessible only via almost vertical cliff faces, hundreds of feet above the canyon floor. The population of the region became more concentrated, perhaps acting upon the conviction that there is safety in numbers.

The Cliff Palace clearly was located with defense rather than esthetic appeal primarily in mind. The only access to it was by hand- and footholds—large enough for only fingertips and toes—carved in the rock. Afraid of something or someone (there is now no indication of what or whom), the Anasazi built fortresses unique among indigenous Americans. Their main building material was sandstone, laid in a mortar made from mud reinforced with tiny stone chips; the masonry was covered with a thin coat of plaster. Deliberately small doorways, set a foot or two above the floor, were probably intended to keep out winter drafts; they could be covered with rectangular sandstone slabs about 1 inch (2.5 centimeters) thick.

The Cliff Palace was first excavated and stabilized by Jesse Walter Fewkes of the Smithsonian Institution, in 1909, more than twenty years after it was first seen by European Americans. Archeological work did not resume until about eighty years later, when evidence was discovered of a hierarchical society: a wall divides the Cliff Palace into two parts. It has also been suggested that the site was not continuously occupied except by a small caretaker population of perhaps 100 people. Then, its twenty-three large kivas would have accommodated larger numbers who gathered there only on special occasions, perhaps for the distribution of surplus food. The kiva, traditionally described as a ceremonial room, was a sunken, usually circular chamber entered through an opening from the “plaza” above. It had a ventilated hearth, and ledges and recesses surrounded the central space. The Anasazi may have used the Cliff Palace as living quarters during the winter lull in the agricultural year. The investigation of the site continues

Mesa Verde was abandoned quite suddenly, around a.d. 1300. The Anasazi left so much behind that it has been suggested that their departure was hasty.

But that is speculation, and other sources suggest that they depleted the resources of the region, leading, through a tragic path of famine and internal wars, to the demise of their culture. Others cite the migration of Navajos and Apaches from the north, and yet others a fifteen-year drought at the end of the thirteenth century. For whatever reason, the Anasazi departed, leaving behind them the amazing and mysterious ruins of an architecture that is one of North America’s greatest archeological treasures.

Menier chocolate mill, Nolsiel, France

2007-07-04T06:33:00.002-07:00

The Menier chocolate mill at Noisiel, Marne-la-Valleé, was at the heart of a factory complex of industrial structures associated with Menier’s chocolate-manufacturing business. The multistory mill, built between 1872 and 1874, demonstrated an innovative design approach that frankly exposed its structure and materials, using the latter for decorative effect. It is widely regarded as the first building in continental Europe to have been constructed with an iron frame and non-load-bearing masonry walls and has been described as “one of the iconic buildings of the Industrial Revolution.”

In 1816 the pharmacist Jean-Antoine-Brutus Menier opened premises in Paris to sell his medicinal powders to chemists and hardware shops. Later he expanded his business to include chocolate-coated medicines and chocolate confectionery. Having outgrown his Paris base, in 1825 he transferred to Noisiel on the River Marne, where he purchased a mill to grind powders. Following his death in 1853, his son Emile-Justin took over the business, transferred its pharmaceutical arm to St. Denis and diversified into rubber production in a factory on the outskirts of Paris. The Noisiel plant was given over entirely to chocolate production.

Between 1860 and 1867 Emile Menier commissioned the architect Jules Saulnier (1817–1881) to redevelop the plant, constructing new buildings and improving the existing premises to better support the chocolate-making process. The factory would earn the nickname “the cathedral” because of its architecture. In 1869 Saulnier, working with the engineers Logre and Girard, prepared designs for replacing the timber-framed water mill that spanned the river, in order to house three new turbine wheels; he first chose stone as the principal material. Interrupted by the Franco-Prussian War of 1870, construction did not commence until 1872. By then Saulnier had revised the design and the outcome has been described as his masterpiece. The structural frame of the six-story chocolate mill was of puddled iron, diagonally braced to achieve a distinctive effect across the upper three levels of the facade Saulnier likened the resulting pattern to the girders of a lattice bridge. The non-load-bearing, 7-inch (18-centimeter) yellow brick infill walls were decorated with diaper work and ceramic tile inlays with flower and cocoa-bean motifs, mainly in reds, dark yellow, and black. The frame was supported by a skeleton iron structure resting on the substantial stone piers that had carried the earlier timber-framed building, and floors were constructed of shallow brick arches between I beams, which were in turn carried by the main frame. The water-driven turbines were located between the piers. The interior was disposed to house the cocoa-bean milling process, and to free the third level of columns, its floor was suspended from the roof trusses. The spacing of columns and windows varied slightly, and deliberately, contributing to the artful composition of the facade.

Under Emile Menier’s entrepreneurial leadership the business continued to expand. In the 1880s it established a factory in London and acquired cocoa plantations in Nicaragua, as well as a sugar refinery and a merchant fleet. It even established a railroad company to move materials and products. More buildings were constructed at Noisiel, utilizing the most advanced constructional methods and materials. A self-contained village was founded in which most of the factory’s 2,000 employees lived in detached two-family houses or, if single, in hostels. The

complex was set in extensive landscaped grounds. At the turn of the century the Menier chocolate business was the world’s largest, and it reached its hey-day before World War I. Decline was probably inevitable.

Between 1971 and 1978 the British confectionery company Rowntree-Mackintosh progressively purchased the Menier company, including its Noisiel factory, where chocolate continued to be made until 1993. The multinational Nestlé, which has owned Rowntree-Mackintosh and its subsidiaries since 1988, has taken over the Menier factory as Nestlé-France’s headquarters, conserving the original buildings at a reported cost of Fr 800 million (U.S.$107 million). The chocolate mill has been made the focal building in the redevelopment by architects Robert and Reichen, and is used for a boardroom, reception rooms, and directors’ offices. The French government has registered it as a Monument Historique

Menai Suspension Bridge

2007-07-04T06:33:00.001-07:00

The many achievements of the Scots engineer Thomas Telford (1757–1834) include bridges over the River Severn at Montford, Buildwas, and Bewdley, all built in the 1780s. In the following decade, as engineer for the Ellesmere Canal Company, he designed and constructed aqueducts over the Ceiriog and Dee Valleys in North Wales. Temporarily returning to Scotland, with William Jessop he built the Caledonian Canal, more than 900 miles (1,440 kilometers) of highland roads, and harbor works at Dundee, Aberdeen, and elsewhere. From 1810 he was engaged as principal engineer—William Alexander Provis was the resident engineer—to construct a highway between the Shropshire county town of Shrewsbury and Holyhead in northwest Wales. It is widely agreed that his masterpiece is the Menai Suspension Bridge (1819–1826), which carries that highway across the Menai Strait, linking Bangor in mainland Wales with the island of Anglesey. It was the first large-scale chain-link suspension bridge and at that time the longest span bridge ever erected.

In 1782 a meeting on Anglesey examined complaints concerning the operation of the ferries at Porthaethwy, Llanfaes, Llanidan, and Abermenai that for centuries had been the only means of crossing the Menai Strait to the Welsh mainland. Increasing traffic across had led to delays and overcharging, and many of the boats were neglected and in dangerously poor condition. Alternatives to the ferries were canvassed, including an embankment and stone or timber bridges. With 4,000 vessels passing through the strait each year, those proposals were met with reasonable objections, and nothing was done. In October 1785 the Irish Mail Coach service was inaugurated between London and Holyhead on Anglesey, where travelers took ship for Ireland. The situation was further exacerbated in 1801, when the Act of Union demanded that Irish members of Parliament travel between Dublin and London, partly via the primitive Holyhead-Shrewsbury road and of course the ferry. Nevertheless, it was not until 1810 that Parliament commissioned Telford to recommend the line for a link across North Wales and Anglesey, including a bridge across the Menai Strait.

Attempts to improve only parts of the existing road were disastrous, so in 1816 Telford was appointed its resident engineer. His 69-mile (110-kilometer) stretch of the 93-mile (150-kilometer) toll highway (now the A5 national road) was probably the best road in Britain. It was up to 40 feet (12 meters) wide, with easy gradients and excellent bridges; moreover, its well-designed construction meant that it could accommodate heavy wagons.

Telford offered three alternative designs for the Menai Strait bridge, and that for a suspension structure was accepted. Finally, after forty years of debate and quibbling, the first stone was laid on 10 August 1819, and in the face of opposition from ferry proprietors and businesspeople in the ferry ports, construction work commenced. Including the approaches the bridge is 1,500 feet (459 meters) long. The approaches, completed in the fall of 1824, were carried on seven stone piers—three on the mainland side and four on the Anglesey side—supporting arches. The 579-foot (177-meter) main span, with its 24-foot (7.4-meter) dual carriageway, was suspended 100 feet (30 meters) above the water by sixteen chain cables hung from 153-foot-high (47-meter) massive battered towers—they were called “pyramids”—at each end, built of limestone from Penmon Quarries at the north end of the strait. Telford designed the piers to stand above the low-water mark, to facilitate inspection of the masonry.

The suspension chains were fabricated in wrought iron from Hazeldean’s foundry near Shrewsbury. Each consisted of 935, 9-foot-long (2.75-meter) eyebar links, about 3.5 inches (83 millimeters) square in cross section, pinned together. To prevent rusting between fabrication and placement, they were immersed in warm linseed oil. Tunnels were excavated in rock to provide anchorage, and the first section of chain was secured at the mainland end, draped over the top of the eastern pyramid and left hanging to water level. The procedure was repeated on the Anglesey side. The central section, weighing nearly 28 tons (25.4 tonnes), was maneuvered into position between the towers on a barge and connected to the end sections before being raised to the top of the tower by block and tackle and the strength of 150 men, thus completing the span. The chains were all placed in ten weeks, by July 1825. Iron rods suspended from them were bolted to iron joists that carried a timber deck. The Menai Strait bridge was opened to the public on 30 January 1826. Its completion and Telford’s Shrewsbury-Holyhead road reduced the travel time between London and the Irish Sea port by a quarter.

Without stiffening lateral trusses, Telford’s bridge soon proved unstable in the winds that swept through the strait, causing the road deck to oscillate. In 1826 a gale caused 16-foot (4.9-meter) deformations in the deck before it failed; although severely damaged, the bridge survived and was strengthened. A more rigid timber deck was incorporated in 1840 and that was replaced by a steel structure in 1893. Further changes were made in a major renovation of 1938–1941, ostensibly to cater for modern automobile traffic (the previous load limit per vehicle was 5 tons [4.6 tonnes], although it might also have been defense related). The arched openings in the towers were widened to allow easier passage of larger vehicles, the carriageway was strengthened, and the chains were replaced with steel cables and realigned. The bridge remains in use.

Mausoleum at Halicarnassos - Anatolia, Turkey

2007-07-04T06:32:00.000-07:00

The tomb of King Mausolos, known as the Mausoleum, was a structure impressive enough to merit inclusion among the seven wonders of the ancient world, and its name has passed into many European languages to describe any imposing funereal structure. It was designed by the Greek architect Pythios (some sources credit Satyros also) and decorated with works by the sculptors Scopas, Bryaxis, Timotheus, and Leochares. Because it survived for sixteen centuries, descriptions abound; combined with archeological evidence, they provide a good idea of the monument’s appearance.

Mausolos (reigned ca. 377–353 b.c.) was a Persian satrap (governor) of Caria in southwestern Anatolia—a region so remote from the Persian capital that it was virtually independent. With a view to extending his power, Mausolos moved his capital from Mylasa in the interior to the coastal site of Halicarnassos, with its key position on the sea routes and large safe harbor, on the Gulf of Cerameicus. In 362 b.c. he joined the ill-starred rebellion of the Anatolian satraps against Artaxerxes II, but anticipating defeat, withdrew from the alliance in time. From then on he became the almost autonomous king of a large domain including Lycia and several Ionian cities northwest of Caria, later forming coalitions with the island city-states of Rhodes and Cos.

Mausolos undertook major urban design projects in Halicarnassos: a defense system, civic buildings, and a secret dockyard and canal. But the most interesting of all his public works was the planning of his great tomb. Conceived during his lifetime, it was initiated probably after his death by Artemisia II, who was at once his sister and his widow, and who for three years was sole ruler of Caria. She died in 350 b.c. and was buried with Mausolos in the uncompleted tomb. According to Pliny the Elder (a.d. 23–79), the craftsmen, realizing that the tomb was a monument to their own creativity, elected to finish the work after their patroness died.

Sited on a hill above Halicarnassos, the tomb rose 140 feet (43 meters) into the air from the center of a stone podium in an enclosed courtyard. A stair flanked by lions led to the top of this platform, whose outer walls were arrayed with statues, including an equestrian warrior at each corner. Its rectangular, tapered pedestal of white marble, with base dimensions of about 120 by 100 feet (37 by 30 meters), was 60 feet (18.3 meters) high. Its faces were carved with reliefs of Greek legends, including battles between centaurs and Lapiths, and Greeks and Amazons. The pedestal supported a colonnade of thirty-six 38-foot-high (11.6-meter) Ionic columns that housed a sarcophagus of white alabaster decorated with gold in a burial chamber. The tomb was roofed with a 22-foot-high (6-meter) stone pyramid of 24 steep steps, crowned with a 20-foot (6-meter) marble chariot bearing statues of Mausolos and Artemisia. Sculptured friezes of people, lions, horses, and other animals adorned every level of the Mausoleum; tradition has it that each of the famous sculptors was responsible for a side.

Under Memnon of Rhodes, Halicarnassos resisted Alexander the Great in 334 b.c. But it successively fell to Antigonus I (311 b.c.), Lysimachus (after 301 b.c.), and the Ptolemies (281–197 b.c.), after that retaining its independence until the Roman conquest in 129 b.c. Throughout all this conflict and for 1,600 years, the Mausoleum remained intact until a series of earthquakes shattered the columns and damaged the roof, bringing down the stone chariot. By the fifteenth century a.d. only the base remained. When the Crusader Knights of St. John of Malta invaded the region, they built a castle on the site and in 1494 used the stones of the Mausoleum to fortify it against an expected Turkish invasion.

Within twenty-five years almost every block of stone had been placed in the walls of their Castle of St. Peter the Liberator. Before grinding much of the Mausoleum’s surviving sculpture into lime for plaster, the knights selected many of the pieces to adorn their castle. They renamed the city Mesy; today the ancient site is occupied by the town of Bodrum In 1846 Charles Newton of the British Museum began a search for vestiges of the Mausoleum. By 1857 he had uncovered sections of the reliefs and pieces of the roof. He also found a broken wheel from the stone chariot and, finally, the statues of Mausolos and Artemisia that had ridden in it for twenty-one centuries. All that remains of this wonder of the ancient world can now be found in the Mausoleum Room of the British Museum.

Maunsell sea forts - England

2007-07-04T06:31:00.000-07:00

The coasts of Kent and Essex Counties, England, overlook the Thames Estuary, the only sea route to London. Throughout World War II it was constantly endangered by German minelayers, U-boats, and the Luftwaffe. From 1939 until 1942 the British navy patrolled the area; then a series of seven sea forts was built to permanently guard the river mouth. They were an innovative architectural and engineering achievement. The reinforced concrete and steel structures were entirely prefabricated in a Gravesend dry dock, floated to their locations, sunk, and anchored on the bottom of the sea, up to 9 miles (14 kilometers) off the coast. Although not as large as the now almost commonplace offshore oil and gas platforms around the world, the sea forts predated them by about five years, and the six so-called “Texas Towers” that form part of the U.S. lighthouse system by almost twenty.

Two kinds of forts, one for the navy and another for the army, were designed by the civil engineer Guy Maunsell. Even when war was little more than a threat, he submitted several proposals for seaward defenses, but it was not until October 1940—over a year after the outbreak of war—that the Admiralty commissioned him to design a prototype sea fortress. His initial costly proposal, for a 2,900-ton (2,640-tonne) pontoon supporting a gun battery, was shelved by the government. But when France fell, the Admiralty was moved to action and asked Maunsell to produce five sea forts for the Royal Navy.

The naval sea forts were essentially steel gun platforms with two 6-inch (150-millimeter) cannon and a Bofors antiaircraft gun. The huge structures were assembled by Holloway Brothers at the Red Lion Wharf, Gravesend, towed downriver by three tugs,

and sunk by flooding their hollow pontoon base. Two were positioned in the estuary off the Essex coast and two off the Kent coast. Each fortress had a crew of about 100, who lived, provisioned for more than a month, in the two 26-foot-diameter (8-meter), 7-story concrete “legs” that supported the main platform, with its guns, radar, and control tower. The first was sited at The Roughs in February 1942. Sunk Head followed on 1 June, and Tongue Sands was completed about a fortnight later. Knock John was ready for action on 1 August. The fifth was never built.

The army sea forts, also designed by Maunsell, were England’s response to German air attacks on the strategic Liverpool docks via the undefended Mersey Estuary. It was decided to build five in the Mersey mouth and seven in the Thames Estuary. Each self-contained fort had living quarters for twenty-four men and comprised seven steel platforms supported on four 160-foot (49-meter) concrete legs. Four were gun towers with 3.7-inch (95-millimeter) cannon; a fifth was armed with a Bofors gun; the sixth was a searchlight tower; and the last was for radar. They were linked high above the sea by tubular steel catwalks that also carried power and fuel lines between the platforms. Their disposition was based upon the proven layout of shore gun batteries. In the event, only three were built on each side of England. Those in the Thames Estuary, constructed by the engineers who built the navy forts, were towed downriver in pairs and lowered by winches at strategic sites: The Great Nore, Shivering Sands, and Red Sand—all rather closer inshore than the navy counterparts. The pontoon bases used in the earlier structures would have been unsuitable in shallower water, where tidal currents constantly shifted the seabed; instead, Maunsell designed a self-burying footing that firmly anchored each tower in place. Construction began in August 1942, and the last tower was completed sixteen months later. At each site, the Bofors platform was erected first to defend the construction crews as they assembled the rest of the fort.

There is now no way to measure the passive deterrent effect of the Maunsell forts, but during their short active life they accounted for the destruction of twenty-two enemy aircraft and about thirty flying bombs. Because the Ministry of Defence believed that a combination of bad weather and tidal action would quickly destroy them after the war, no thought was taken for their disposal. For a few years after 1945 the naval forts were serviced by the Thames Estuary Special Defence unit, and two were temporarily adapted as lightships. Difficulty of access in storms led to that being discontinued; in fact, Tongue Sands was wrecked in bad weather in 1966. Only Knock John and The Roughs survive. After May 1964 the former, together with Red Sand and Shivering Sands army forts, was occupied at various times and for various periods by pirate radio stations, until the last was shut down under the Offshore Broadcasting Act in July 1967. The Roughs continues to have an eccentric postwar history.

It lies slightly north of the Thames Estuary off Harwich, and in September 1967, when it was still outside British territorial waters, a former British army officer named Paddy Roy Bates formally (and it must be said legally) annexed it as the Principality of Sealand, going aboard as the “prince” with his family. In the late 1990s a consortium of U.S. Internet entrepreneurs set up the world’s first offshore data haven there, offering prospective clients security for their computer operations, free from the interference of legislation.

The army forts also went into decline. For a short while, under the control of the Anti-Aircraft Fort Maintenance Detachment, they were furnished with improved searchlights and radar installations. Any perceived crisis past, the army stripped all guns and equipment from them in 1956. The Red Sand fort, off the Isle of Sheppey, was abandoned that same year. The Great Nore fort was dismantled in 1958 after being struck by a ship and officially declared a hazard to shipping. In 1959 another vessel collided with the Shivering Sands fort, bringing down one of the towers. Despite their short-lived roles as radio stations, the survivors are now derelict. Their robustness means that their skeletons will stand in the North Sea for some years to come, gaunt confirmation of the proverb “Necessity is the mother of invention.” Guy Maunsell did not survive his great sea forts, dying in 1961 after establishing an international civil-engineering partnership, which continues.

Marib Dam - Yemen

2007-07-04T06:30:00.002-07:00

The Republic of Yemen is located on the southwestern coast of the Arabian peninsula, the region once possessed by the ancient southern Arabian kingdoms that occupied the mouths of large wadis (valleys) between mountains and desert. The first-millennium-b.c. kingdom of Saba sprang up in the dry delta of the Wadi Dhana that divides the Balak Hills. In the eighth century b.c., at the height of their prosperity, the Sabaeans had established colonies along both sea and land trade routes to Israel, and they dominated the region. Their capital, Marib, among the wealthiest cities of ancient Arabia, stood 107 miles (172 kilometers) east of Sana’a, the capital of modern Yemen. It is generally agreed that artificial irrigation was practiced near ancient Marib as early as the middle of the third millennium b.c. About 2,000 years later a dam was built to harness the biannual floods and systematic irrigation was introduced. Some scholars believe that the Marib Dam was the “greatest technical structure of antiquity.”

Around 685 b.c., under King Karib’il Watar, Saba enlarged its borders. Territories were conquered in the southwest of the peninsula; Ausan in the south was defeated and Sabaean rule extended northwest as far as Nagran. In the second half of the sixth century b.c., two kings successively built the Marib Dam near the mouth of the Wadi Dhana, the largest water course from the Yemeni uplands. By impounding water during the two rainy seasons, the dam provided irrigation for some 25 square miles (65 square kilometers) of fields and gardens. Replenished and enriched by sedimentary deposits, this agricultural land supported a population estimated to be about 30,000.

The first dam was a simple earth structure, 1,900 feet (580 meters) long and probably only 13 feet (4 meters) high, built between rocks on the south side

of the wadi and a rock shelf on the north. Its location a little downstream of the wadi’s narrowest point permitted space for a natural spillway and sluices. Around 500 b.c. a second 23-foot-high (7-meter) earth dam was built. It was triangular in section; both faces sloped at 45 degrees and the upstream side was faced with stone set in mortar. The final form of the Marib Dam was not built by the Sabaeans.

Late in the second century b.c. the Himyarites, a tribe from the extreme southwest of Arabia, established their capital at Dhafar and gradually absorbed the Sabaean kingdom, gaining control of South Arabia. They undertook the next major reconstruction of the Marib Dam, building a new 46-foot-high (14-meter), 2,350-foot-long (720-meter), stone-faced earthen wall, incorporating sophisticated hydraulic systems. It was nearly 200 feet (60 meters) thick at the base, built on a stone foundation, and created a lake that was probably 1.5 square miles (4 square kilometers) in area. At each end of the wall there were sluices, constructed with what has been described as the “finest ancient masonry … in Arabia,” through which water was channeled to extensive irrigation networks on both sides of the valley floor. The southern sluice system had a 10-foot-wide (3.5-meter) spillway about 23 feet (7 meters) below the top of the dam. The northern system included a spillway and a massive channel outlet between the spillway and the earth wall. It carried water via a 3,300-foot-long (1-kilometer), 40-foot-wide (12-meter) stone-lined earthen conduit, rectangular in cross section, to a distribution point that fed 12 irrigation canals. The discharge flowing into the conduit was controlled by a pair of gates; it also passed through a large settling basin.

When the Romans began to trade with India directly via the sea routes, the South Arabian economic monopoly was broken. The overland route declined, and social structure began to disintegrate. The Himyarite dynasty was toppled by an Ethiopian invasion in a.d. 335, reestablished toward the end of the fourth century, and again overthrown by the Ethiopians in 525. The Himyarites were absorbed into the wider South Arabian population.

The Marib Dam was regularly breached, usually by overtopping, during the extreme floods that occurred about once in fifty years. Just as regularly—for example, in a.d. 450 and 542—substantial repair work was undertaken. But when it was overtopped in 575, it was not repaired. Its final destruction was later recorded in the Koran (632–650), attributed to the judgment of Allah: “But they turned aside, so We sent upon them a torrent of which the rush could not be withstood, and in place of their two gardens We gave to them two gardens yielding bitter fruit. …” There is also a Yemeni proverb, “The Marib dam was destroyed by a mouse.’ Archeologists and engineers attribute its collapse to lack of adequate, regular maintenance or to the gradual failure of the foundation. Whatever the case, deprived of their water supply, the lifeblood of their crops and gardens, thousands of people from Marib returned to the nomadic life or migrated northward. The collapse of the dam expedited Bedouin insurgence from the Najd, and Islam was introduced around 630.

In December 1986 a new 125-foot-high (38-meter) earth dam was officially inaugurated. It closes off the Wadi Dhana a little under 2 miles (3 kilometers) upstream of the old dam site. Like its ancient predecessor, it was designed to impound water for irrigating the Marib plains; a 12-square-mile (30-square-kilometer) lake with almost a capacity of 437 million cubic yards (400 million cubic meters) has transformed 45,000 acres (18,000 hectares) of desert into productive farmland.

Maria-Pia Bridge - Oporto, Portugal

2007-07-04T06:30:00.001-07:00

Located at the mouth of the Douro River, Oporto is the capital of northern Portugal and the second-largest city in the country, rising steeply from the deep river valley. In 1875 the railway between Lisbon and Oporto was almost complete, and the final problem facing its builders was crossing the Douro. An international competition attracted only four entries, three from France and one from England. Gustave Alexandre Eiffel’s winning proposal for the “transparent” Maria-Pia Bridge was not only the least expensive—two-thirds that of the next tender and only one-third of the highest price—but it also involved revolutionary structural design.

Although Eiffel is best remembered for the Eiffel Tower in Paris, much of his professional life was given to building bridges. Upon his graduation from the École Centrale des Arts et Manufactures in 1855, he was employed by a firm in southwestern France that produced steam engines and railroad equipment. In 1858 it won a contract to erect a railway bridge over the Garonne River near Bordeaux; Eiffel oversaw the construction, which was completed in 1865. The following year he set up business as a “constructor,” designing and fabricating metal structural work, especially in wrought iron. After 1872 foreign contracts came his way, and three years later he designed the Maria-Pia railway bridge in Oporto.

Eiffel supported the railroad deck 190 feet (57 meters) above the river with a graceful, filigreed wrought-iron arch spanning 525 feet (160 meters); the approaches to the center span were borne on lacy framed pylons of varying heights to accommodate the sloping banks. Construction started in 1877, and

the bridge was built in just a year and ten months, without the need for temporary scaffolding directly supported on the ground—a masterly piece of design. The structural system involved several other technological innovations, not least the design analysis methods. Civil engineers already knew how to calculate for statically indeterminate beams, but the force method needed to predict the behavior of this kind of structure, although propounded a decade earlier, had been taken seriously only a year before Eiffel designed the bridge. It has been asserted that this was the first application of the analysis of a statically indeterminate structure other than a beam, and that Eiffel discovered the method by himself.

The pioneer technique was to be used in many large arches, including two in Oporto. The first came soon after: the wrought-iron Dom Luís I Bridge for pedestrian and vehicular traffic (1886), designed by the French engineer Téophile Seyrig. It is noteworthy that it weighed almost twice as much as the 1,800-ton (1,630-tonne) Maria-Pia. The second arch in Oporto was built almost eighty years later: the 900-foot-span (270-meter) reinforced concrete Arrábida Bridge (1963) was designed by the Portuguese Edgar Cardoso. And Eiffel himself reused the design in France: in 1880 Leon Boyer of the Ponts et Chaussées (Bridges and Highways Department), who was aware of the success of the Maria-Pia Bridge, invited him to build a bridge across the La Truyère River near Garabit on the railroad between Marvejols and Neussargues. The 550-foot (165-meter) span Garabit Viaduct, completed in 1884, incorporated all the innovations of the revolutionary Portuguese structure: it comprised a 1,500-foot-long (450-meter) wrought-iron truss girder, carried to the arch on variable height piers and extended by brick approach viaducts to a total length of 1,880 feet (564 meters).

In 1996 UNESCO designated Oporto a World Heritage City. The Maria-Pia Bridge, threatened with demolition after it was replaced by a new rail crossing in 1991, is now safe and awaiting a new use appropriate to its significant place in the history of engineering.

Maillart’s bridges

2007-07-04T06:29:00.004-07:00

The Swiss engineer, architect, and artist Robert Maillart (1872–1940) exploited the structural strength and expressive potential of reinforced concrete to generate a modern form for his bridges. By using simple construction concepts he developed graceful structures based on flat or curved reinforced concrete slabs. Amongst his radically innovative ideas were the mushroom slab, the deck-stiffened arch, the open three-hinged arch, and the hollow-box arch. Maillart’s biographer David Billington (1997, 2) asserts that the engineer’s “elegance arose from structure itself and not from an extraneous idea of beauty.”

Taken singly or together, Maillart’s bridges are engineering and architectural feats that elegantly demonstrated, as Le Corbusier claimed in Vers une Architecture (1923), that engineers recognized (long before architects) that beauty could be achieved through thoroughly defining and solving problems. That new approach to design lay at the foundation of modem architecture.

Maillart studied civil engineering at Switzerland’s Federal Technological Institute in Zürich under Wilhelm Ritter, an expert on reinforced concrete. Graduating in 1894, he worked in private and government engineering offices, mostly on railroad, road, and bridge projects.

Unreinforced concrete was first used in 1865 for a multiple-arch bridge on the Grand Maître Aqueduct between the River Vanne and Paris. The invention of reinforced concrete is credited to Joseph Monier, a French gardener who in 1867 patented molded planters made of cement mortar reinforced with iron-wire mesh. Over the next decade there followed several bridge patents. Because French law prevented him from building bridges, Monier sold the patents to contractors Wayss, Freitag, and Schuster, who built Europe’s earliest reinforced concrete bridges in Germany and Switzerland.

Around the turn of the century the French engineer François Hennebique built reinforced concrete bridges at Millesimo, Italy (1898), and Châtellérault, France (1900). Therefore, while his designs were probably the most elegant, Maillart was not the pioneer of reinforced concrete bridges. In 1902 he established his own firm, specializing in reinforced concrete design and construction. By then he had already built a 100-foot-span (30-meter) bridge over the River Inn at Zuoz; its innovative slenderness and flatness created a stir in professional circles. There followed the 115-foot (35-meter) Thurbridge near Billwil (1903) and another single 167-foot (51-meter) arch across the Rhine near Tavanasa (1905, since demolished), identified by some scholars as marking the birth of a modern architecture that reintegrated art and technology.

Maillart moved his practice to Russia in 1912 and produced a number of factories, warehouses, and office buildings in Riga, Charkov, and Kiev. Following the October 1917 Revolution, he returned to Switzerland and in 1919 set up a consulting design practice in Geneva, later opening branch offices in Bern and Zürich.

From 1925 he built several remarkable bridges in Switzerland of two principal structural types: stiffened-slab arches, such as the 140-foot (43-meter) span over the Val-Tschiel near Donath, of 1925; and three-hinged arches in which the arch, roadway, and stiffening girder were integrated into a monolithic structure, exemplified by, among others, the Schwandbach Bridge (1933) in Bern Canton and the Salginatobel Bridge (1930) over the Salgina Valley in Graubunden Canton. The latter is a hollow, box-concrete arch bridge with a span of 295 feet (90 meters) and a rise of 43 feet (13 meters). The slender arch rib deepens from the supports to the quarter-span points, at which it becomes integral with the concrete road deck and tapers again to the midspan hinge. Salginatobel Bridge is widely regarded as an exceptional monument of modern architecture, a piece of structural art. In 1991 the American Association of Architects and Engineers designated it an International Historic Civil Engineering Landmark. It has also been called “the most spectacular and classic example of [its] type in the world.”

Ritter had urged his students to think of shapes and forms that could not be analyzed easily by mathematical calculation. Clearly, Maillart had learned that lesson, and his visual imagination and intuition were a major part of his approach to engineering; just as clearly, his subtly beautiful bridges evidence a thorough comprehension of the nature of forces in a structure. His deep appreciation of the properties and behavior of reinforced concrete permitted him to develop innovative, light sculptural forms. Through his bridges, Maillart, virtually unknown and unacknowledged before about 1930, became internationally famous as a designer of sophisticated concrete structures.

Maiden Castle - Dorset, England

2007-07-04T06:29:00.003-07:00

The ancient British hill fort now known as Maiden Castle (from mai-dun, Celtic for “great hill”), about 3 miles (4.8 kilometers) southwest of modern Dorchester, grew from a neolithic village to become the largest pre-Roman fortress among nearly 1,400 in England. Indeed, it was one of the most extensive in western Europe. Still visible 2,000 years after its massive ramparts were completed, the fort crowns a low saddleback chalk hill south of the Frome Valley. Its strength did not lie (as in the case of others) in its siting, but rather in the sheer size and scale of its fortifications. By the middle of the first century b.c., four rings of ditches and steeply sloping earthen walls, in places as much as 90 feet (28 meters) high and reinforced by timber palisades or drystone structures, occupied an area of 100 acres (40 hectares). Within the defenses, the long axis of the fort is over 0.5 mile (0.8 kilometer) and its inner circumference about 1.5 miles. It was a remarkable engineering achievement, not only in terms of its monumentality, but also because of its organic nature, by which it grew over twenty centuries.

Maiden Castle has a long prehistory, revealed by archeological studies first undertaken by Mortimer Wheeler in 1934–1938; further excavation took place in 1985–1986 under the direction of Niall Sharples. The first earthwork was a neolithic causewayed camp (ca. 4000 b.c.) consisting of a single ditch and bank

defending an area of about 12 acres (4.8 hectares). It was followed after half a century by a 1,750-foot-long (537-meter) bank barrow, crossing the center of the fort from east to west. About 1,000 years later settlers built burial mounds on the site, after which it seems to have been abandoned for some time.

After about 700 b.c. various tribes settled Britain, and most of the southwestern region now known as Somerset and Dorset was occupied by the Durotriges. They secured their lands against rival tribes with hill forts: such places as Hambledon Hill, Hod Hill, South Cadbury, Spettisbury Rings, and of course Maiden Hill, which some scholars suggest was their capital. Around 600 b.c. these Iron Culture settlers incorporated the existing earthworks into their own defenses—an earth rampart augmented by a timber palisade—enclosing about 15 acres (6 hectares) at the east end of the saddleback. There was continual growth: limestone walls were added to parts of the ramparts, and it seems that around 450 b.c. a westward extension was constructed. Sometime before the third century b.c., the encircling fortifications were enlarged, and entrances with double gates were constructed at the east and west ends; the entire hilltop—some 45 acres (18.2 hectares)—was secured. The height of the earth walls was increased, perhaps late in the second century b.c., and yet another rampart and ditch were built around the perimeter. Further enlargement took place a century later. Although it may be that not all Dorset hill forts were continuously occupied, and that some were simply used as havens in times of danger, evidence suggests that Maiden Hill was a permanent settlement, and at the middle of the first century a.d. perhaps 5,000 people were living within what they believed to be the safety of its walls. There were made streets, and archeologists have discovered graves, storage pits, and other pits for refuse—it might be said, sanitary landfill.

The Romans launched a full-scale invasion of Britain in a.d. 43, moving westward across the country. The Roman historian Suetonius claims that twenty of the southwest hill forts fell quickly to the II Augusta Legion, come from Strasbourg under the general Titus Flavius Vespasianus (later to become Emperor Vespasian). They reached Maiden Castle within the year. The Durotriges were renowned warriors, accustomed to hand-to-hand combat. At longer range, they used slings and were prepared to defend their town with them: ammunition dumps within the ramparts held a reserve of 40,000 large pebbles brought from Chesil Beach. The Romans chose to turn their war machines against the well-defended east gate, defended by slingers on its four ramparts. Overwhelmed by the weight of numbers and the superior tactics and weapons technology of the invaders—especially the catapults that launched missiles from beyond the slingers’ range—Maiden Castle surrendered, although not before offering savage resistance.

After three millennia the huge, spectacular hill fort had become obsolete, and it was abandoned within about thirty-five years. Many of the former inhabitants moved to the new Roman town of Durnovaria (Dorchester), others to the century-old Celtic village in the shadow of Maiden Castle. In about A.D. 370 the Romans built a temple in the precincts of the fort, but it too was abandoned when they withdrew from Britain only 100 years later. The site is now maintained and managed by English Heritage.

Ma’dan reed houses - Iraq

2007-07-04T06:29:00.001-07:00

The reed houses that form part of the distinctive culture of the Ma’dan, or Marsh Arabs, of southeastern Iraq are an architectural achievement because they result from pushing available resources to their limits. Descended partly from the ancient Sumerians and Babylonians, this seminomadic people, now numbering perhaps 200,000, have for millennia inhabited Lake Hammar and the surrounding marshlands in the Tigris-Euphrates Delta, about 200 miles (320 kilometers) south of Baghdad. Not only have they developed a sophisticated house form using a single building material—the stalks of the prolific giant reed (Fragmites communis)—but they have also created the very land upon which their houses and farmsteads stand.

The Ma’dan villages are irregular clusters of small islands constructed by alternating layers of reed mats and layers of mud dredged from the marsh bottom. Thus, paradoxically, much of the fertile land is actually floating on the water. Each island has its house and buffalo paddock, and communication between them is by means of narrow canoes (mashuf) of bitumen-coated wood, propelled through the shallow water with long poles. The Ma’dan fish, hunt waterfowl and pigs, breed water buffalo, and raise crops of paddy rice and great millet. Many domestic necessities—beds, cots, baskets, and canoe poles—are woven from reeds. In short, until recently the Ma’dan have lived in harmony with the ecosystem of their harsh but bountiful environment.

The reed house (mudhif) is constructed around a framework made by tying the giant reeds—they can grow to 20 feet (6 meters) long—to make bundles that taper from about 1.5 feet to 6 inches (45 to 15 centimeters). The thick ends are stuck into the mud floor of the island in opposing pairs and then bent and lashed together, with a substantial overlap at the top, to form a row of parallel parabolic arches, at about 6-foot (2-meter) centers. The builders even use a tripod of bundled reeds as scaffolding for this part of the work. The primary frames are stabilized with closely spaced, much thinner reed bundles (like purlins) around the perimeter of the house. The completed framework is covered with intricately woven split-reed mats to form the integrated walls and roof. The upper parts of the end walls are enclosed with a curtain of the same material, and four or five reed “columns” are erected to support a framework to which a decorative lattice is fixed, always to beautiful effect. Depending on the length of the reeds used for the arches, the house can be 12 feet (3.7 meters) wide; the length is indeterminate, and buildings up to 100 feet (30 meters) have been recorded. Furnishings are sparse: the reed floors are covered with carpets, and there is a clay hearth for making coffee. The distinctive house form has a long pedigree,

being illustrated on a clay plaque dating from the fourth millennium b.c. found in excavations of Sumerian Uruk. That fact, and the appearance of vegetable forms in stone, such as Egyptian papyrus and lotus columns, has given rise to the speculation that all columnar architecture in the protohistoric civilizations (and perhaps beyond) springs from such construction.

The unique culture of the Marsh Arabs is in danger; indeed, it may already be beyond help. Largely as a result of their isolation, they have maintained their traditions and were untouched even by Turkish and British colonialism. Because of high evaporation, the marshes have long been regarded as wasteful of water that could be used for irrigation; a major drainage scheme was proposed in a 1951 report drafted by British engineers commissioned by the Iraqi government. In the 1970s Turkey dammed the Euphrates. But the Ma’dan’s problems started in earnest after 1980, during the Iran-Iraq War. Within two years Iran regained the territory, including the marshlands, taken earlier by Iraq. The marsh dwellers fled as the Iraqi army sent enormous electrical currents through the water to electrocute invading Iranian soldiers. Saddam Hussein’s unrelenting destruction continued after the war.

Following Saddam’s defeat in the Gulf War in 1991, southern Iraqi Shi’ite Muslims launched a guerrilla offensive against his Sunni Muslim government. The uprising was crushed, and many rebels sought refuge in the marshes, supported by the Ma’dan, who are also Shi’ite. To flush them out, in 1992 Saddam began to drain the region systematically, using the 1951 British report. Within a year a network of 20-foot-high (6-meter) dikes was preventing two-thirds of the normal water flow from reaching the marshlands, thus turning much of it into expanses of dried mud. Between the Tigris and the Euphrates Rivers, the man-made Saddam River carried floodwaters directly to the Persian Gulf. A third of Lake Hammar dried up, and thousands of Marsh Arabs moved deeper into the surviving wetlands or fled to Iran and elsewhere. Some sources estimate that fewer than 10,000 remain in Iraq, recognized as a “persecuted minority” by the European Parliament, to pursue their traditional lifestyle. To compound the offense of ethnocide, Saddam’s actions have caused probably irreversible environmental damage. International organizations such as the UN Human Rights Commission, the Supreme Council of the Islamic Revolution in Iraq, and the International Wildfowl and Wetlands Research Bureau have been watching in alarm, but have been powerless to act.

London Underground - England

2007-07-04T06:27:00.002-07:00

London’s underground railroad system, popularly known as “the Tube,” is the oldest in the world. As early as the 1830s Charles Pearson, the city of London’s solicitor, suggested that the mainline stations could be linked by an underground railroad with as many as eight tracks. Despite the potential economic and social advantages of the scheme, it could find no financial backing, and Parliament refused to approve it. The city’s first above-ground passenger service was the London and Greenwich line, opened in February 1836. Within four years it was carrying nearly 6 million passengers annually between the major mainline train stations on the borders of the metropolis and the edge of the central business district. With an area of 60 square miles (154 square kilometers) and a population of 2.5 million, Greater London was then the world’s largest city, and the most crowded, plagued by street congestion.

To find a solution to a worsening problem, the City Terminus Company (CTC) revived the underground railroad idea in 1852 and placed it before Parliament, only to again fail. The following year the Bayswater, Paddington, and Holborn Bridge Railway Company submitted a plan for a different line, ostensibly at half the cost. Parliament endorsed the North Metropolitan line in 1853, and the company promptly had the CTC line approved as part of its own. The Great Western Railway Company agreed to finance construction of the underground in return for direct access to the city. In 1854 an act of Parliament was obtained to begin the Metropolitan Railroad. A sum of £1 million was raised by December 1859, and the following February the first shafts were sunk. The earliest tunnels were made by the “cut and cover” method: a deep trench would be excavated, side walls and roof built, and the ground surface backfilled. The process was expensive and slow, and it created chaos along the route of the railroad, not least of which was the dispossession of citizens and the demolition of buildings, often the homes of the poor. The first trial run was on 24 May 1862, and on 10 January 1863 the Metropolitan Railway opened, the world’s first underground line, between Bishop’s Road, Paddington, and Farringdon Street. There were 38,000 passengers on that first day, and from that moment the London Underground began to grow. In 1868 the first section of the Metropolitan District Railroad from South Kensington to Westminster was opened.

It was soon realized that, a citywide underground network must eventually pass beneath the River Thames. “Cut and cover” methods would not be appropriate to build such lines, but an “old” technology was already in place. Completed in 1843, Marc and Isambard Brunel’s Thames Tunnel had been dug using the former’s tunneling shield, patented in 1818. The machine had been improved in fifty years, and the engineer James Henry Greathead finally built a

lighter and (more importantly) circular version. In 1870, with one Peter Barlow, he drilled the 6-foot-diameter (1.83-meter) Tower Subway Tunnel from Tower Hill to Vine Lane. Its system of elevators and a twelve-seat car, all wound by steam-operated wire cable, was unreliable, and within months it was reduced to a pedestrian passage. Although extremely short-lived, it was the first tube railroad, and the construction method obviated all the disadvantages of “cut and cover.” Greathead’s tunneling machine had a diaphragm within, which segments of the cylindrical, cast-iron tunnel lining were bolted together as the excavator was advanced hydraulically; the gap between the excavation and the lining was filled with cement grout. Because it was circular in cross section, the tube was structurally stronger.

The next route to be completed was the Circle line in 1884. At that time all trains were drawn by steam locomotives, filling the tunnels with smoke and fumes. Steam trains could not operate in the deeper tunnels, and after considering cable-hauled cars, the decision was made to employ electric traction. Most of the transition took place in the first decade of the twentieth century, although the world’s first successful electric tube route, the City and South London Railway, was opened in December 1890. In 1902 an American, Charles Tyson Yerkes, financed the expansion of the network and by 1907 five new lines—Central, Northern City, Bakerloo, Piccadilly, and Charing Cross Euston and Hampstead—were opened, and electrification proceeded. Yerkes formed the Underground Electric Railway Company of London (known as the Underground Group). Between 1902 and 1905, they built the world’s largest power station, at Chelsea, to electrify the District line. Powering the Tube for almost a century, it was closed in 2000 when the Underground moved to the national grid. By 1913, mergers had brought all lines except the Metropolitan, into the group.

Underground services expanded from 1907 through the 1930s. In 1933 the Underground Group and the Metropolitan Railway were subsumed by the London Passenger Transport Board, which managed all public transport systems in the London area. Following World War II (when no fewer than eighty Underground stations served as air-raid shelters for Londoners), the Passenger Transport Board was nationalized and renamed the London Transport Executive, which in turn became the London Transport Board. More administrative changes began in May 2000, with the establishment of Transport for London, an executive body of the Greater London Authority.

In September 1968 the first section, of the Victoria line was opened, and extensions were completed by 1971. In May 1979 the Jubilee line opened, bringing the total number of routes beneath London to eleven: Bakerloo, Central, Circle, District, East London, Jubilee, Metropolitan, Northern, Piccadilly, Victoria, and Waterloo and City. Upgrades and improvements continue. Recently, computer signaling was introduced; the Central line was modernized and the Victoria line converted to automatic operation. The most significant addition to the complex system, begun in 1993, was the construction of the £1.9 billion (U.S.$2.8 billion) Jubilee line extension, the largest engineering project undertaken in Europe since the Channel Tunnel. Completed in May 1999, the new route from Westminster Station to Stratford via North Greenwich (to serve the Millennium Dome) involved negotiating the already crowded undercity with its myriad railroad tunnels, cables, drains, and service ducts, as well as overcoming subsidence problems.

Nearly 80 percent of Londoners working in central London travel to work on public transport, most of them on the Tube. Trains traveling at an average speed (including stops) of 20.6 mph (33 kph) move a total of almost a billion passengers annually over a multilevel underground network—some tubes reach 221 feet (67.4 meters) deep—that extends 45 miles (72 kilometers) east to west and 28 miles (45 kilometers) north to south. The first underground railroad in the world, which began with a track a mere 3.57 miles (5.7 kilometers) long, now covers 250 miles (392 kilometers); 42 percent of that is in tunnels.

Larkin Administration Building - Buffalo, New York

2007-07-04T06:27:00.001-07:00

The Larkin Administration Building (1902–1906) by Frank Lloyd Wright (1869–1959) was his first major public work, built, as he said, “to house the commercial engine of the Larkin Company in light, wholesome, well-ventilated quarters.” It was a milestone in the history of commercial architecture, in terms of both its spatial organization and the exploitation of modern technology. Indeed, some historians identify it as the twentieth-century structure that, more than any other, changed the face of architecture; within a few years it was hailed in Europe. Peter Blake has claimed that it was the “first consciously architectural expression of the kind of American structure which Europeans were beginning to discover to their delight: the great clusters of grain silos and similar industrial monuments that [they] found so exciting in the early 1920s.” (Blake 1964, 55–56). The Larkin Company’s soap-manufacturing and mail-order operations occupied a large urban industrial site between Swan, Exchange, Van Renssalear, and Hamburg streets of Buffalo, in western New York State. Wright’s innovative building on Seneca Street, near the corner of Seymour and Swan, housed the firm’s administrative functions.

Around 1902 Wright realized that different building types called for different esthetic systems. Thereafter, he developed two patently distinct architectures. In his houses he pursued what might be called prairie horizontality—the line of repose that reached its best expression in the Frederick C. Robie House, Chicago (1908–1910). For nondomestic buildings, such as the Larkin Building; Unity Temple, Oak Park, Illinois (1905–1909); and Midway Gardens, Chicago (1913–1917), he adopted “Cubic Purism,” often squat and squarish with symmetrical plans and elevations. The rather severe exterior of the Larkin Building was relieved with sculpture by Richard Bock, who produced a globe of the world, supported by celestial beings and emblazoned with the company name.

The great six-story space in the center of the building—today we think of it as an atrium—was lit by a large skylight. It was surrounded by balconies; lit by high-level windows around the perimeter of the building, they contained the general office spaces, set out (years before their time) on an open plan. In keeping with Wright’s views about the nature of work, and no doubt with those of his client John D. Larkin, the interior espoused nonhierarchical, democratic office planning. There was even an employees’ lounge with a piano, where the company provided a weekly lunch-time concert for the workers; an organ stood at one end of the third story of the atrium. Many of the 1,800 employees worked at long desks running between the outer walls and the atrium. The lighting was an important part of the design; the desks received daylight from two sides: the exterior windows and the atrium. Electric lamps were mounted at the ends of the tables in the ground floor of the central court so that every office worker had well-balanced, shadow-free light. Wright believed in making total architecture and designed the lighting system himself, as well as the steel office furniture. The employees were protected from industrial pollution and the noise of the nearby rail yards by heavy red brick walls, and from undue interior noise by sound-absorbent surfaces. The revolutionary working environment was also air-conditioned, one of the first in the United States.

Just as he separated service rooms from living rooms in his contemporary houses, Wright gathered the services—electrical and plumbing ducts, stairways, toilets (he introduced wall-hung water closets to make cleaning easier), and heating systems—at the outer corners of the main building. “Beating the box” (as he put it), he expressed the service functions as square towers, “freestanding, individual features.”

Responding to criticisms by Russell Sturgess of The Architectural Record, who called it “an extremely ugly building” and “a monster of awkwardness,” Wright said in 1908, “It may be ugly … but it is noble. It may lack playful light and shade, but it has strength and dignity and power.” He went on to claim: “It is a bold buccaneer, swaggering somewhat … yet acknowledging a native god in a native land with an ideal seemingly lost to modern life—conscious of the

fact that because beauty is in itself the highest and finest kind of morality so in its essence must it be true.” His opinions, even if a little arrogant, were confirmed by the great Dutch architect H. P. Berlage, who spoke of the Larkin Building to attentive European audiences. To call it Wright’s magnum opus (exclaimed Berlage) “was not to say enough.” It was a building without equal in Europe, and there was “no office building [there] with the same monumental power.”

The Larkin Company went into decline in the 1930s, and within a decade its world-famous Administration Building was being used as a showroom. In 1949–1950, for “mysterious and untraceable reasons,” it was pointlessly demolished, brick by brick. Today, only a single pier remains—the site was never redeveloped but used as a parking lot—and in 1997 the outline of the building’s footprint was painted where once stood one of the most important achievements of twentieth-century architecture.

Lalibela rock-hewn churches - Ethiopia

2007-07-04T06:26:00.002-07:00

Lalibela is a village in the mountainous Welo region of northern Ethiopia, about 440 miles (700 kilometers) north of Addis Ababa; in the Middle Ages it was known as Roha and was the capital of the Zagwe dynasty. Standing on a rock terrace at an elevation of 8,500 feet (2,600 meters), it is the site of eleven large rock-hewn monastic churches that date from the late twelfth and early thirteenth centuries. Each is architecturally distinctive and all are finely carved inside and out. Declared a UNESCO World Heritage Site in 1978, they are not the earliest such churches in Ethiopia (others predate them by at least 500 years), but they are widely recognized as the most beautiful. Francisco Alvarez, a Portuguese Jesuit missionary, visited Lalibela in the 1520s, the first European to see the churches. He was reluctant to report to his superiors, fearing that they would not believe his account of buildings “unlike any to be seen elsewhere in the world.” Nevertheless, he described them. “hewn entirely out of the living rock, which is sculpted with great ingenuity.” The culturally unique churches are remarkable for that reason: each has been cut from the purple-red volcanic tufa, in some cases 90 feet (27 meters) into the ground. Some of them are connected by tunnels or passageways open to the sky. Even to the modern mind, they are an architectural marvel.

The history of the churches is swathed in mythology. It is probable that King Lalibela (1181–1221) commissioned them. According to legend, angels carried him to heaven when he was affected by a poison that his envious brother had administered; God sent him back to earth with instructions to build the churches and later dispatched angels to continue the work at night. Another account says that the king recruited Indian, Arab, and Egyptian builders, or even “white men” from Jerusalem, a link that is strengthened by the naming of the local river, Jordan. It has been suggested that, upon learning that the Holy City had fallen to Islam, Lalibela wanted to create a “new Jerusalem” in his secure mountain fastness. Tradition has it that the eleven buildings were completed in twenty-four years—archeologists calculate that would have needed 40,000 workers—but the time frame seems too short. Maskal Kabra, Lalibela’s queen, is said to have built one of them to his memory.

The churches stand in two groups flanking the Jordan. Four of them—Bet Medhane Alem, Bet Maryam, Bet Amanuel, and the cruciform Bet Ghiorghis, dedicated to Ethiopia’s patron saint—are in effect huge blocks of sculptured stone standing in deep excavated courtyards and attached to the rock only by their bases. Bet signifies “the house of.” They look like normal buildings, but each one is a single piece. The others must be accurately described as semimonolithic, because they remain attached to the rock by at least one face, whether the roof or walls. For example, although the twin churches of Bet Golgotha and Bet Qedus Mikael share a roof, they have, respectively, one and three facades exposed. Bet Abba Libanos is isolated from the mother rock except for its roof, which is integrated with the overhanging cliff; in front of it stands a large forecourt, cut from the tufa. The other churches are named Bet Danaghel, Bet Debre Sinai, Bet Gabriel-Rufa’el, Bet Merkorios, and Bet Meskel.

The eclectically blended artistic influences are varied—Greek, Egyptian, and even Islamic—and the nature and the extent of the carefully carved exterior and interior walls, ceilings, moldings, and window tracery are just as diverse. Bet Qedus Mikael has smooth exterior wall surfaces, and its interior is austere, decorated with Greek crosses; on the other hand, Bet Golgotha is more ornate, perhaps because it houses the tomb of King Lalibela, and it contains bas-reliefs of saints, the only sculptures in any Ethiopian church. Other churches have painted decoration, mostly with a teaching function, in various states of preservation.

The churches of Lalibela are home to hundreds of monks, clerics, and students, who celebrate liturgies that are the same as they were eight centuries ago. It is the most important pilgrimage site in Ethiopia, a country that includes an island of Christianity in a sea of Islam, and during the major holiday seasons it may be visited by as many as 50,000 devotees. More recently, Lalibela has become a tourist attraction, precisely because of its spectacular churches, and draws over 10,000 secular visitors a year. Inevitably, there is a tension between conservation and development. But because tourism is the village’s only real source of wealth and is encouraged by the central government, a compromise must be reached. In 1996 the European Community earmarked EUR4.7 million for shelters to replace the corrugated-steel roofs that covered Bet Medhane Alem, Bet Maryam, Bet Meskel, Bet Amanuel, and Bet Abba Libanos from damage caused by torrential rains, and an international architectural competition was held. Structures designed by the first-prize winners, Teprin Associati of Italy, were completed by December 2000. UNESCO and the Ethiopian Department of Preservation of Cultural Heritage are urging restoration of the deteriorating fabric of the churches.

Lal Quila (the Red Fort) - Delhi, India

2007-07-04T06:26:00.001-07:00

Lal Quila (the Red Fort) was built between 1638 and 1648 at the command of the Mughal emperor Shah Jahan (who also built the Taj Mahal) as the royal residence in his new capital, Delhi. The fort, representing the highest achievement of Mughal architecture, contained all the accoutrements befitting a center of empire: public and private audience halls, domed marble palaces, luxuriously appointed private apartments, a mosque, and exquisite gardens. Much of the opulence has gone, but in its heyday its magnificence would have been unparalleled, as boasted by an inscription on one of its walls: “If on Earth be an Eden of bliss, it is this, it is this, none but this.”

Delhi stands at the western end of the plain of the Ganges. The epic Mahabharata speaks of it as a thriving city built about 1400 b.c., although archeo-logical reality suggests it was settled about 1,000 years later. The first city named Delhi was founded in the first century b.c. by Raja Dhilu; southwest of the modern location, it had six successors. Its Mughal history is relevant here. In 1526 Babur, the first Mughal ruler, established Delhi as the center of an empire that would unite vast areas of south Asia for the next two centuries. His son Humayun built a new city near Firuzabad but it was leveled when Afghan Sher Shah Suri overthrew him in 1540. He built a new capital, Sher Shahi, as the sixth city of Delhi. Once more eclipsed when the emperors Akbar and Jahangir moved their courts elsewhere, Delhi reached prominence, even glory, in 1638, when Akbar’s grandson Shah Jahan moved his capital from Agra to establish the seventh city of Delhi: Shahjahanabad, now known as Old Delhi. Most of it is still embraced by Shah Jahan’s walls, and four of its seventeenth-century gates still stand. He also built Lal Quila as the royal residence within the new city.

Almost immediately, Shah Jahan commissioned the architects Ustad Hamid and Ustad Ahmad to design a fitting royal residence—the Red Fort—at the northeastern corner of Shahjahanabad. It was completed within about ten years. An area of 124 acres (50 hectares) was enclosed within 1.5 miles (2.4 kilometers) of formidable defense walls. It was flanked by the Yamuna River on the eastern side, which fed a moat 76 feet (22.8 meters) wide and 30 feet (9 meters) deep. Thick red sandstone walls (from which the fort derives its name), punctuated by turrets and bastions, rose 60 feet (18 meters) from the river; those on the other side stood up to 112 feet (33.5 meters) above the surrounding terrain. Two of the six main entrances—the Lahori Gate and the Delhi Gate—survive. Now the moat is dry and the Yamuna flows almost a kilometer away, but Lai Quila towers above the modern city of Delhi that spreads out to the west.

The buildings within the walls are all carefully arranged on the long north-south and shorter east-west axes of the octagonal plan. Although they reveal the delicate work that can be found in all Mughal architecture, they exemplify the later phase of the style, characterized by the increasing use of marble, elaborate floral decoration of external surfaces, and the proliferation of tall minarets and bulbous domes. Shah Jahan seems to have preferred the flowing plant motifs inspired by the European sixteenth-century herbariums that had been perfected by his father’s artists. The walls of carefully cut marble were patterned with precious and semiprecious stones and surfaces were decorated with inlaid flowers of hard stones in many colors.

Immediately inside the fortified Lahori Gate was the Chatta Chowk, a vaulted two-story arcade containing thirty-two shops. East of it, on the same axis, was another gate called Naubat Khana (Drum House), also two stories high, from which musicians played martial, music for the emperor five times a day, or announced the arrival of important guests. Further east on the axis and across a courtyard stood the Diwan-i-Am (Public Audience Hall), ornamented with gilded stuccowork and hung with heavy curtains. There the emperor, seated in a canopied, marble-paneled alcove set with precious stones, would hear through his prime minister the complaints and petitions of the commoners. The Diwan-i-Am was also used for state functions. At the eastern terminus of the short axis of the plan stood the Rang Mahal—(Palace of Colors), its roof crowned with gilded turrets. It housed the emperor’s wives and mistresses. The interior was richly decorated with painting. Its ceiling, overlaid with silver and gold, was reflected in a pool in the marble floor. The Nahr-i-Bihist (Stream of Paradise) flowed through its center, feeding small water channels that flowed to cool the other rooms of the Red Fort.

The north-south axis, through the center of a courtyard that separated the Diwan-i-Am and the Rang Mahal, was flanked by sumptuous pavilions. In the Diwan-i-Khas (Hall of Private Audiences), the emperor met with his courtiers and dignified guests. Standing on a plinth and supported by thirty-two pillars, the white marble hall was decorated with floral patterns of precious stones. At its center the fabled Peacock Throne (carried off to Persia in 1739) stood on a white marble dais under a ceiling inlaid with silver and gold. South of that building lay the emperor’s private apartments, the Khas Mahal. On their east side was a large sitting room that opened to a cantilevered gallery, where each sunrise the emperor appeared before his subjects. At the northern end of the large square in front of these buildings stood the Hammam (Royal Bath). Built of marble and extravagantly decorated with inlay, glass, and paint, it comprised three apartments that were also used for private meetings. Shah Jahan’s son Aurangzeb built the Moti Masjid (Pearl Mosque) within an enclosing wall beside the Hammam in 1659–1660. At the northern end of the long axis stood a three-story octagonal tower, Shah Bhurj—the shah’s private working area. At the southern end Shah Jahan built the Mumtaz Mahal, a palace for his favorite daughter Jahanara Begum.

Mughal power waned in the eighteenth century. The British captured Delhi in 1803, and the city was the focus of India’s first war of independence—the British still prefer to call it the Indian Mutiny—in 1857. In 1911 the colonials moved their imperial capital from Calcutta to Delhi and began to build the eighth city, New Delhi, officially inaugurated in 1931. India finally expelled the British in 1947, and the nation celebrates its liberty by flying the Indian flag above Lal Quila each 15 August, Independence Day.

The Krak of the Knights - Syria

2007-07-04T06:25:00.001-07:00

Once described as “the key of Christendom,” the concentric castle known as the Krak of the Knights stood on the 2,000-foot-high (611-meter) southern spur of the Gebel Alawi, commanding the strategic Homs Gap in the Orontes Valley between Syria’s Mediterranean coast and the hinterland. The easternmost in a chain of five castles, it was well placed to control the trade routes between Asia Minor and the Levantine Coast. The formidable fortress represented the height of achievement in medieval military architecture and was described by Lawrence of Arabia as one of the “best preserved and wholly admirable castles in the world.”

Medieval warfare was a cycle of conquest and consolidation. Builders were as important as soldiers to an army and throughout the religious wars known as the Crusades (1096–1291) both sides built scores of fortified strongholds, the ruins of which can be found throughout the Middle East. In 1095 Pope Urban II decreed that he would absolve anyone who fought to reclaim the Holy Land for Christendom, a promise that ignited two centuries of conflict. On the face of it, there was a religious reason—pilgrims could not reach Jerusalem—but Urban II’s decision was also prompted by a combination of ulterior political motives. The Byzantine Empire was staggering in the face of Turkish expansion; European feudal lords were anxious to profit from their military strength, and some states wanted to exploit their naval might in the Mediterranean. And there was opportunity for the papacy to make the most of rising religious fervor to gain control of the mind of western Europe.

Kings and barons squandered the lives and the wealth of their subjects as they led all social classes against Islam. From time to time the Crusaders controlled parts of Turkey, Syria, Lebanon, and Palestine, capturing Jerusalem from the Seljuk Turks in 1099 and holding it until Salâh al-Dîn regained it in 1187. An earlier Islamic Castle of the Kurds on the site of the Krak was taken, albeit temporarily, by Raymond de St.-Gilles in 1099, and he again laid siege to it, without success, in 1102. Tancred of Antioch occupied it permanently from 1110, and thirty-two years later the Count of Tripoli gave it to the Knights Hospitallers. They invested a great deal of wealth and skill to develop it into “the most distinguished work of military architecture of its time.”

The Krak comprised almost 8 acres (3 hectares) and incorporated various buildings in an inner bailey

with a high curtain wall. That was in turn surrounded by an outer bailey within a second, slightly lower curtain wall—a consistent feature of the concentric castles of the period. The inner bailey was built probably soon after 1110, but it was extensively repaired and refurbished in the late twelfth and early thirteenth centuries after a series of earthquakes after 1157. The later builders thickened the curtain wall and added a glacis and water-filled moat. They also reinforced the towers. The outer bailey, with a complicated, sharply angled (and therefore highly defensible) eastern gateway, was built in stages. The inner curtain, with rectangular towers that hardly projected from the wall, dominated the outer and stood quite close to it. The 16-foot-thick (4.9-meter) outer curtain had eight projecting round towers on the north and west sides, and their loopholes covered every direction. Two towers protected the north barbican, or fortified gateway, from which a narrow ramp led to the inner bailey. All the walls, inner and outer, had castellated galleries, and there were extensive machicolations. The portico of the inner bailey was added around 1250. If necessary, up to 4,000 soldiers and 300 knights with their horses and equipment could be garrisoned in the Krak, and enough provisions could be stored in its warehouses, stables, and cisterns to resist a five-year siege. But early in the thirteenth century only 2,000 men occupied it, with provisions for just one year. Throughout Crusader times, there was a dependent burgus (walled suburb) associated with the castle.

The castle was also used as base from which to harass the surrounding country held by Islam. Called by one Muslim writer “this bone in the throat of the Moslems,” it easily withstood attacks from Nûr al-Dîn in 1163 and 1164 and by Salâh al-Dîn in 1188. It finally fell in April 1271 after a siege of only a month by the Mameluke sultan, Baybars. He had breached the outer curtain but had no way of overcoming by force the second line of defense with its three massive towers and talus. It was through a forged document commanding the Hospitallers to surrender that the Krak of the Knights was finally taken—by treachery and not by power. In 1291 the Crusaders were expelled from Acre, their last stronghold, and they withdrew to several Mediterranean locations until Turkish expansion in the sixteenth century. The important positive result of the years of war was that cultural exchange with the more scientifically advanced Islamic world contributed much to the enlightenment of Western civilization.

King’s College Chapel - Cambridge, England

2007-07-04T06:24:00.002-07:00

The architectural historian G. E. Kidder Smith correctly identifies King’s College Chapel as “one of the great rooms in architecture.” Initiated by King Henry VI in July 1446, it was not completed until 1537. Even then, it was acknowledged by many to be one of Europe’s finest late-medieval buildings. It was an architectural achievement in that it epitomized the English High Gothic, its filigreed stone frame, large windows, and exquisite fan vaulting all demonstrating the pinnacle of structural refinement that had taken almost 400 years to achieve.

Henry VI (1421–1471), described as a “a pious and studious recluse” incapable of governing, succeeded his father Henry V as king of England in 1422. Just a month or so after the infant monarch ascended the English throne, he was also proclaimed king of France. Interrupted by the Wars of the Roses in 1461, his reign resumed in 1470, only to be cut short by his murder the following May. When he reached the age of sixteen he was deemed old enough to rule for himself and, despite a reputedly rebellious youth, by the time he was nineteen Henry had grown to be religious. Neglecting matters of government, he turned his attention to the establishment of two educational foundations: Eton College near Windsor (1440–1441) and the Royal College of the Blessed Virgin Mary and St. Nicholas of Canterbury (now known as King’s College) at Cambridge University (1441) provided for seventy scholars drawn from Eton. Henry set out detailed instructions for both colleges and at both his primary concern was for the construction of a chapel. One writer has obsequiously observed that the king’s “selfless piety accounts for the form of the chapel at King’s, which was conceived … as a personal testament of faith.” Certainly, King’s College Chapel had no precedent in other university colleges; its design has more links with the choirs of the great English cathedrals.

Henry VI laid the first stone of King’s College on Passion Sunday 1441, and over the next three years he proceeded to compulsorily acquire real estate in the center of Cambridge. Houses, shops, and even a church were demolished as the land was cleared for his grand scheme—a great court of which the chapel was to form the north side. In the event, only the chapel would be built. Henry laid its foundation stone on 25 July 1446; the architect was his master mason, Reginald of Ely. The Wars of the Roses impeded progress, and Henry’s chapel was left to be finished by others.

The construction was spasmodic, to say the least. It resumed in 1476 under Edward IV and his architects John Wolrich and Simon Clerk (after 1477) but again ceased when Henry VII succeeded to the throne in 1485. The fellows of the college soon drew his attention to the fact that “the structure magnificently

begun by royal munificence now stands shamefully abandoned.” When the king visited Cambridge in 1506, only five bays had been built, but they had a timber roof, and the open end was boarded and decorated with the arms of the Knights of the Garter painted on paper. Prompted by his mother, and for political reasons, Henry VII decided to finish the chapel. In 1508 work recommenced on a large scale. Although Henry died the following year, his will provided for the work to be completed. By 1512 the stone frame was finished, and his executors found extra money for the magnificent fan vaulting—called by some “the noblest stone ceiling in existence”—designed by the master mason John Wastell. Within three years the structure was complete, and the painted-glass main windows—the most complete set to survive from Tudor times—were finished in 1537. The latter works had been executed under Henry VIII, and when he died in 1547, King’s College Chapel was internationally recognized as an architectural masterpiece.

Much of the unique early design of the chapel can be ascribed to Reginald of Ely, who continued to supervise the work until 1461. The interior is a single vast space 289 feet (88 meters) long and 40 feet (12.2 meters) wide, under a soaring, 80-foot-high (24.4-meter) vault. Some scholars believe that the fan vault was proposed to replace a much simpler lierne vaulting system during master mason Simon Clerk’s appointment. King’s College Chapel has no side aisles, but ranges of minor chapels and vestries are accommodated between the deep buttresses on the north and south sides. The only subdivision of the entire space, and that just in part, is made by a half-height choir screen, above which the intricate forms of the high vaulting can be seen marching in stately procession toward the altar. The carved oak screen (ca. 1531–1536), in the uninformed mimetic manner of the early English Renaissance, was commissioned by Henry VIII; it is emblazoned with his monogram and Anne Boleyn’s. Its clumsy design provides an apt foil for the high refinements of English Gothic architecture seen everywhere else in the building. Almost 70 percent of the walls above the dado (that is, all except the buttresses) are made of painted glass, making the huge interior light and airy and accentuating the stone lacework of the vaults.

Jantar Mantar - Jaipur, India

2007-07-04T06:24:00.001-07:00

Jantar Mantar (“instruments and formulae”), the open-air observatory designed by Maharaja Sawai Jai Singh II, India’s last great classical astronomer, stands at the entrance to the palace in the old city of Jaipur. Built between 1728 and 1734, the group of large, modern-looking masonry structures is in fact a collection of astronomical instruments. They measure local time to an accuracy of a few seconds; the sun’s declination, azimuth, and altitude; the declination of fixed stars and planets; and they predict solar eclipses. It is the largest of the observatories established by Jai Singh II in five principal Hindustan cities; others were in Delhi, Ujjain, Mathura, and Varanasi (Benares). Only two survive: the one at Mathura was quarried for its stone and those at Ujjain and Varanasi are partly in ruins. Jantar Mantar is a remarkable architectural achievement: large buildings constructed with such exactness that they can be used as scientific instruments.

Jai Singh II, a member of the Hindu Kachhawaha dynasty, came to power at the age of thirteen. As well as being a capable general, he was so politically and intellectually gifted that the Mogul emperor Aurangzeb conferred on him the title of Sawai (literally, “a man and a quarter”). Mogul power was declining toward the end of the 1720s, but Jai Singh’s kingdom was prospering. The water supply in his fortified hillside capital, Amber, was strained by increasing population, so he moved his seat of government to the plains. In 1727 he commissioned the Bengali architect Vidyadhar Bhattacharya to design a new walled city about 125 miles (200 kilometers) southwest of Delhi and named it Jaipur. Unlike the laissez-faire contemporary north Indian cities, Jaipur’s plan was based on urban design principles found in the Hindu architectural treatise, the Shilpa Shastra. The city was divided by a right-angle grid of wide primary and secondary streets, and further by lanes and alleys, into seven rectangular zones following the caste system, related to occupations and trades. The central rectangle housed the royal complex—the palace, administrative buildings, the women’s palaces, and the Jantar Mantar.

Jai Singh II was interested in religion and the arts and sciences and his court became a magnet for savants, artists, and philosophers. He was especially interested in astronomy and acquired a multilingual library on the subject, including the works of Ptolemy and Euclid, Persian and Hindu astronomers, and modern European and Muslim sources. Beginning in 1728, he built the Jantar Mantar in Jaipur. Within high walls on three sides, the observatory covers an area of about 5 acres (2 hectares). It contains fifteen

astronomical instruments built of local stone and marble. Six had solar measurement functions, eleven were for observing the night sky, and one was unfinished. These large, architecturally refined devices, capable of achieving much greater accuracy than small brass instruments, were based on Islamic astronomical theories. Most were derived from those commissioned by the fifteenth-century Byzantine ruler Ulugh Begh for the well-equipped observatory built in Samarkand in 1428.

The largest instrument at Jaipur is the equatorial sundial, a 90-foot-long (27.5-meter) straight ramp pointing toward the celestial pole. Graduated masonry quadrants on each side are centered on the nearest edge of the ramp, whose shadow marks local solar time to an accuracy of a few seconds. It was also used to determine the celestial longitude of the sun and to establish the exact time of the equinoxes. The design of another instrument, the Jai armillary sphere, has been attributed to Jai Singh II himself. It comprises two marble hemispherical bowls, each about 13 feet (4 meters) in diameter, set into the ground; their surfaces are inscribed with coordinate lines of celestial latitude and longitude. A small ring was suspended on wires over the exact center of each, and during the day its shadow marked the exact position of the sun. At night an observer could enter a room under the bowls to take sightings on the stars. The two bowls are complementary, and alternating their use within a two-hour changeover allowed continuous observation. There are also several sundials: a vertical one, hemispherical ones, and a smaller equatorial one that can measure time to about 20 seconds’ precision. Twelve smaller zodiacal instruments—one for each sign—and similar in design to the equatorial sundial, were used for observing the latitudes and longitudes of the sun and the planets. There are also two sets of tall rectangular columns arranged in circles and calibrated to allow reading of the altitude and azimuth of celestial bodies.

Finally, the astrolabe, a star chart engraved in a metal disc, is about 6.5 feet (2 meters) in diameter—six or seven times the usual size of contemporary examples—and made of a seven-metal alloy that Jai Singh had developed to minimize variations caused by temperature changes. Adjustable rulers allow the calculation of rising and setting points of the stars and planets for the accurate casting of horoscopes. That esoteric function underlines a fact that may become obscured as we marvel at the mathematical sophistication of the Jantar Mantar. It is simply this: that despite Jai Singh II’s erudition and urbane universalism, his great observatory and the others like it sprang in part from a religious and not a purely scientific source. In excellent repair after being reconstructed by Chandra Dhar Sharma Guleri in 1901, the Jantar Mantar at Jaipur was declared a national monument in 1948.

Jahrhunderthalle - Breslau, Germany

2007-07-04T06:23:00.002-07:00

The Jahrhunderthalle (Centennial Hall) of 1911–1912 in what was formerly the city of Breslau in Germany (now Wroclaw, Poland) was a major milestone in the development of the enclosure of large public spaces by reinforced concrete structures. It was by far the largest of several pavilions built in Scheitniger Park (now Szczytnicki Park) to house the 1913 centennial of Germany’s liberation from Napoleonic rule. The Jahrhunderthalle was intended to serve as an exhibition space, an assembly hall, and a venue for concerts, sporting events, and other entertainment.

Wroclaw in southwestern Poland fell to the Prussian armies of Frederick the Great in 1741, to eventually be renamed Breslau. By the early twentieth century the city had become a major center for the arts, in part because the Expressionist architect Hans Poelzig was director (1903–1916) of the Royal Art and Craft Academy. Breslau’s largely German population then exceeded half a million, and the government decided to create what it called a “metropolis of the east.” Accordingly, the architect Max Berg, director of Frankfurt am Main’s City Building Department, was appointed City Building Commissioner. In Frankfurt, he had been deeply involved with the construction of the city’s Festhalle (1907–1909), designed by Friedrich von Thiersch; that experience was significant for his work in Breslau. He had also designed the development plan for Berlin.

Beginning in the second half of 1910, Berg conceived and developed the structure of the Jahrhunderthalle. Engineering calculations were made by Gunther Trauer of the City Building Department. Trauer described it as an “incredibly clever” design, although he admitted that it was “unusually large and challenging” for him. Nevertheless, he rose to the challenge, and the building is evidence of an admirable symbiosis between architect and engineer. Together they produced two feasibility studies—one that employed a fire-resistant steel structure and another of reinforced concrete—and prepared two sets of contract documents. Because the City Board of Directors was adamant that the exhibition building should be “no-risk [and] fire-proof,” the former structural system was virtually precluded because of the bulkiness of concrete-cased steel. On the other hand, such a huge reinforced concrete space had never before been built, and conservative members of the board doubted its practicability. However, after six months of deliberations Berg’s reinforced concrete proposal was accepted in June 1911 on the condition that the cost be reduced by 10 percent.

The client’s insistence on functional flexibility had generated difficulties for Berg. Conventional wisdom pointed to a long space for an exhibition hall and a

central plan for the other events. The first design was based upon a longitudinal plan, but that was soon modified to become a central circular space with four semicircular apses that are reached through enormous arches. As built, the hall encloses almost 60,000 square feet (5,600 square meters) of floor space. It provides standing room for 10,000 people; the seating capacity is only 6,000. The 137-foot-high (42-meter) central space is roofed with a 212-foot-diameter (65-meter) dome, formed by 32 half-arches of reinforced concrete—left exposed for acoustic purposes—springing from the massive poetic substructure to a tension ring at the apex. In its day it was the widest monolithic dome in the world. The vast interior is lit by four tiers of curtained clerestory windows, supported by the half-acrches and continuous around the entire structure, which diminish in height as they rise. That gives the dome the appearance of a series of concentric rings. The apses, also structurally formed from reinforced concrete half-acrches, have walls glazed in the same manner, adding to the stunning impact of the space. Although the structural system was revolutionary, the spatial organization (and the overall form that it yielded) had a Renaissance quality, very like the Church of S. Maria della Consolazione (1503) at Todi, Italy, by Donato Bramante and Cola di Caprarola. Berg’s inspiration was complex: he drew upon the spirit of Gothic architecture and the esthetic theories of the Frenchman Durand and the Hollanders Lauweriks and Berlage. The monumentality of the huge building evokes the romantic, unbuildable Beaux Arts projects of Boullée and Ledoux; at the same time, Berg avoids ornament for its own sake. The result is that, artistically, the Jahrhunderthalle denies the çonfident inventiveness of its engineering; at least, that is the impression from outside the building.

The contract for the reinforced structure was won by the Dresden firm of Dyckerhoff and Widmann; the Lolat-Eisenbeton Company of Breslau undertook the smaller associated buildings. Work began at the end of August 1911; the foundations were completed two and a half months later, and the building was completed in the amazingly short time of fifteen months, well before the centenary celebrations were due to begin.

The Jahrhunderthalle was a landmark building, and while some architectural writers dismiss Berg’s work as “equivocal,” others believe that the “structural audacity” he demonstrated in this magnum opus had great influence on the German Expressionist architects (including Poelzig) who flourished between 1910 and 1925. Indeed, Jerzy Ilkosz (1994, 81) has asserted that it “was the first major achievement in the pantheon of Expressionist architecture.” Following World War II the Germans were expelled from Breslau and in August 1945 the city, again named Wroclaw, reverted to Poland. The building was renamed Hala Ludowa (the People’s Hall).

Itaipú Dam - Brazil/Paraguay border, South America

2007-07-04T06:23:00.001-07:00

Built between 1975 and 1991, the Itaipú Hydroelectric Power Plant is situated on the Paraná River between the cities of Guaira, Brazil, and Salto del Guaira, Paraguay. Including the reservoir created by its dam, the system extends about 125 miles (200 kilometers) along the river; it is the largest hydroelectric facility in the world. It supplies about a quarter of Brazil’s south, southeast, and west-central regional demand, and nearly 80 percent of Paraguay’s total electrical energy. In 1995 the American Society of Civil Engineers nominated Itaipú as one of the seven wonders of the modern world, on the basis of its “advances, engineering challenges and long-term significance.” Beyond the staggering scale of the engineering project, Itaipú is also important politically (because of the dual ownership of Brazil and Paraguay) and environmentally.

The two nations recognized the energy potential of the Paraná River, the seventh largest in the world, that forms their mutual border. In 1966 they signed the Ata do Iguaçu (Act Iguaçu), a joint statement agreeing to equally share the energy. In 1970, a consortium comprising the U.S. firm IECO and the Italian company ELC successfully tendered to conduct a thorough evaluation of resources, and in April 1973 the Treaty of Itaipú set out details for the creation of the power plant. A year later the Itaipú Binacional corporation was established to administer the financing, construction, and management of the dam. Construction work began in January 1975 and reached its peak in 1978, when about 40,000 people were engaged on the massive undertaking, described by one source as “a labor of Hercules.” The first of eighteen 700-mega-watt generating units (nine serve each country) was commissioned in December 1983, and Paraguay’s electrical grid went on-line in March 1984. Brazil followed in August, and the whole system, generating 12,600 megawatts, was operational by April 1991. Two more generators will be installed by 2003, bringing Itaipú’s capacity to 14,000 megawatts. The dam was projected to cost U.S.$3.4 billion but the final cost reached between $1.8 billion and $20 billion.

Itaipú’s complex series of dams was built after the Paraná was rerouted through a 1.3-mile-long (2.1-kilometer) diversion channel, completed in October 1978, which entailed removing over 50 million tons (45.5 million tonnes) of earth and rock. Together, the great walls stretch 4.8 miles (7.7 kilometers) across the Paraná River, impounding a 125-mile (170-kilometer) reservoir that holds 28.54 billion tons (26.4 billion tonnes) of water. Tourist brochures boast that the dams contain enough concrete to build five Hoover Dams and enough steel for 380 Eiffel Towers. The main hollow gravity-type concrete dam, with a crest height of 640 feet (196 meters), is connected to the spillway (on the right bank) by a concrete buttress-type wing dam, which in turn is linked to a small earth- and rock-fill dike. On the left bank another rock-fill structure links the main dam and an earth-fill dam. The partly submerged, 1,055-yard-long (968-meter) powerhouse sits on the riverbed at the toe of the main dam; fifteen of the generators are in the main powerhouse and the others on the diversion channel.

The resettlement of people—Ava-Guarani Indians and Mestisos—on reservations and the disruption of their lives have had undesirable social effects, both on the displaced people and their new neighbors. Among other consequences, especially in the early stages of dam construction, was the enormous impact on natural vegetation. The binational Forest Management Project, initiated in the late 1970s, aimed to maintain ecological equilibrium and sustainability within the surrounding forests. Reforestation programs and the creation of a number of forest reserves eventually reduced the potential damage by half. It is estimated that 11.5 million plant species were rescued. Fauna rescue and relocation programs saved thousands of animals, birds, and insects, representing over 400 species.

Captive breeding programs will eventually allow the release of rare and endangered creatures into their natural habitat. The Itaipú project has demonstrated that, with careful management, even large-scale socioeconomic development is compatible with environmental conservation.

Ironbridge, Coalbrookdale - Shropshire, England

2007-07-04T06:22:00.003-07:00

Coalbrookdale is regarded by many as the birthplace of the Industrial Revolution. The town of Ironbridge on the eastern bank of the River Severn is the location of the world’s first metal bridge. Designed in 1775, the gracefully arching prefabricated cast-iron structure, appropriately named Ironbridge, was fixed to its masonry abutments in the summer of 1779. Spanning 100 feet (30 meters), the bridge supports itself without a bolt or a rivet in the entire structure! In terms of the creative application of new materials and technology, it remains one of history’s great architectural and engineering feats, the product of the fervent inventiveness of optimistic industrialists, opening the way to the modern era of iron- and steel-framed buildings.

Coal and limestone mining and iron smelting made the River Severn, which reaches the sea through the Bristol Channel on England’s west coast, one of Europe’s busiest waterways. In 1638 one Basil Brooke patented an iron-making process and built a furnace at Coalbrookdale. Seventy years later the operation was acquired and overhauled by the entrepreneurial Bristol Quaker Abraham Darby I, an ironmonger and brass founder. In 1711 he developed a cheaper means of smelting iron by using coked coal as fuel rather than charcoal. The process liberated iron production from fuel restrictions—industrialization initially meant deforestation—as well as making very large castings possible.

Within a couple of years Darby and his partner, Richard Ford, developed what was a minor business producing mainly pots and pans into the world’s leading ironworks. After a few decades the Coalbrookdale Company and its subsidiary Lilleshall Company had expanded to own mines, forges, factories, and farms throughout the region. The burgeoning iron-, brick-, and pottery works in the parishes of Madeley and Broseley, facing each other across the Severn Gorge, brought workers flocking to the district. That dramatic population growth and the obvious increase of commercial and industrial traffic meant that the local ferry, precariously approached down steep, slippery banks, soon proved inadequate for local needs.

Abraham Darby II had proposed to bridge the Severn between Madeley Wood and Benthall but the project lapsed when he died in 1763. It was left to his son, Abraham III, to carry out the project. With the eager cooperation of the squire of Broseley, ironmaster John Wilkinson, in 1775 young Darby convened a meeting of potential subscribers to plan a bridge. The group obtained Parliament’s approval for a structure of “cast-iron, stone, brick or timber.”

The world’s first cast-iron bridge was designed by the Shrewsbury architect Thomas Farnolls Pritchard, who two years before had suggested using the new material for such projects. He proposed a single-span bridge, estimated to cost £3,200, because intermediate piers would obstruct traffic on the busy river. Work began in November 1777. When Pritchard died in that year, Darby assumed responsibility for completion. The components were cast in the Upper or Lower Furnace at Coalbrookdale during the winter of 1778–1779, ready for erection the following summer. Some of the castings—there were 453 tons (384 tonnes) in all—were almost 80 feet (25.5 meters) long, and the Coalbrookdale Works had to be altered to accommodate production. Beginning in May 1799, the prefabricated iron structure took only three months to put together. The parts were ingeniously designed to allow assembly simply by fitting projections into slots and tightening the joints with cast-iron wedges—a totally interlocking structure that, as noted, has no riveted or bolted connections. Ironbridge is a semicircular arch of 100 feet, 6 inches (30.5 meters) span, made by joining two half-arches that were each cast as a single piece. It supports a 24-foot-wide (7.3-meter) deck 40 feet (12 meters) above the Severn.

Costing about twice as much as first estimated, it was opened as a toll bridge (to recoup some of the expense) on New Year’s Day 1781. Within three years earth movement caused some noncritical cracking in the ironwork. The bridge survived a severe flood in 1795, and in 1802 the masonry abutments were replaced by timber. In turn those were replaced by the cast-iron arches that one sees today. Doubts about the stability of Ironbridge led to suggestions about demolition in 1926 but nothing happened. In 1934 it was closed to vehicles and listed as a historical monument. The Shropshire County Council assumed ownership in 1950, and extensive restoration was undertaken in the 1970s. The bridge now comes under the control of English Heritage. In 1986 UNESCO designated the Ironbridge Gorge a World Heritage Site, noting that “all the elements of progress developed in an eighteenth century industrial region can be found [there]. … The blast furnace of Coalbrookdale … is a reminder of the discovery of coke, which, together with the bridge at Ironbridge, the first metallic bridge in the world, had considerable influence on the evolution of technology and architecture.”

Inuit snow houses

2007-07-04T06:22:00.001-07:00

The Inuit—“the real people”—of Alaska, Arctic-Canada, northeastern Siberia, and Greenland sometimes build shelters out of water, or at least water in one of its solid states, snow. The highly sophisticated design and construction of that kind of igloo (the Inuit word for house) is a major architectural achievement, employing a technology that turns a challenging resource to creating a not merely adequate but ideal house form.

The oldest identifiable lnuit date from about 2000 b.c. Some of them followed immense migratory herds of bison, caribou, and musk ox across the Bering Strait into North America. Since two-month summers made agriculture impossible in their harsh, treeless environment, the Inuit relied for their food on hunting and fishing. Although some Inuit have now become westernized and eat supermarket food, fish and sea mammals remain the mainstay of the traditional diet of many, and groups still follow a seasonal nomadic cycle through their lands. In comparison with other hunter-gatherer cultures, the Inuit have highly developed technologies, craftsmanship, and art. The dogsled is used for long-distance transportation of large loads, and the maneuverable kayak (sealskin-covered canoe) has long been a model for Western societies. Inuit weapons are fashioned from ivory, bone, stone, or sometimes copper and often decorated with elaborate carving. Their clothing—parka, trousers, mittens, boots, and snow goggles—is often made of caribou skins.

It should not be thought (as the stereotype has it) that all Inuit live in snow houses. They have three traditional dwelling types. A summer house is essentially a caribou-, walrus-, or sealskin tent. A winter house is partially excavated and usually built of stone, with a whalebone or driftwood frame supporting a moss or sod covering. Then there is the circular dome-shaped snow house that some groups use as a winter dwelling. But it is more commonly used by hunters as a temporary shelter while traveling on long journeys.

The igloo is built with carefully shaped blocks of snow about 4 feet long, 2 feet high, and 6 to 8 inches thick (about 1.3 by 0.65 by 0.15 meters), weighing about 45 pounds (20 kilograms). The house can be up to 18 feet (5.5 meters) in diameter, with ample headroom for the occupants. Snow texture and consistency is critical, and the suitable hard-packed snow is usually found on a north-facing slope. Tiny pockets of air trapped between the crystals provide a remarkably effective means of thermal insulation. For maximum structural strength, the first row of blocks is set out in a circle. The blocks are shaped to form a kind of ramp beginning at the front of the igloo, as the base of a self-supporting continuous spiral. As the walls rise to merge into the roof, successive tiers of blocks tilt more and overhang more as they rise, until they converge to form the dome, which is closed with a large fitted cap-block. This method allows the builder to work alone if necessary. The cracks between the blocks are packed with soft snow. Once the first two circuits are completed, it is possible to construct an igloo even during a blizzard, because the structure acts as a windbreak. When intended to be occupied for a long time, the igloo has another low wall of snow blocks placed around it, and the space between the two walls is filled with loose snow, improving thermal insulation.

The entrance is a narrow passage, high enough to admit a crawling person and curved to stop the penetration of cold winds. Additional storage vaults may also form part of the house. The translucent snow provides a little light inside the igloo, and sometimes an ice window is employed. A small ventilation hole is cut in the dome. The floors in larger, long-occupancy igloos are often concave, so that cold air falls into a pool. The remainder of the floor surface is covered with furs, while others hung on pegs trap an air layer against the walls, providing interior warmth without melting the snow. The heat generated by the occupants’ bodies and by lamps or camping stoves raises inside temperatures enough to allow the Inuit to move about naked in their houses of snow.

Inka road system - Peru

2007-07-04T06:21:00.002-07:00

The brief but glorious ascendancy of the Inka lasted for about sixty years from a.d. 1476. At that moment their empire, Tahuantinsuyu (Land of the Four Quarters), was the largest nation on earth. Ruled from the Andean capital, Qosqo, it covered 2,000 miles (3,200 kilometers) north to south and 200 miles (320 kilometers) inland. The empire’s northern quarter, Chinchaysuyu, extended beyond what is now Colombia; the southern quarter, Collasuyu, reached as far as central Chile; the eastern quarter, Antisuyu, included the eastern Andean foothills in modern Bolivia and Argentina; and the western quarter, Guntisuyu, embraced the Pacific coast.

A critical means of sustaining Inka power over subject peoples was a system of primary and secondary roads whose total length has been estimated to be 25,000 miles (40,000 kilometers), comparable to the communication infrastructure of the Roman Empire, and achieved without the advantage of the wheel or large draft animals. Quite apart from the variety of the terrain, the Inkan transportation network was a great engineering feat, and the response to that diversity—mountains and valleys, snow, deserts, and swamps—makes the accomplishment the more remarkable. Near the coast they were dusty tracks, sometimes built on causeways to keep them free of blown sand or sometimes simply pegged out; in swamps they were built on stone viaducts; and in high rain- or snowfall regions they were paved with cobbles or flagstones. Steep slopes were negotiated by means of steps, often cut into the living rock.

The roads sat within a hierarchy, at the apex of which were the two north-south royal, or Inca, roads linking Qosqo with the four quarters of the empire. One crossed the Cordillera from what is now Colombia to Argentina, and the other followed the coastal plains from northern Peru to northern Chile. They were linked by several crossroads. The rest of the primary network consisted of “principal” or “rich” roads and “big” or “broad” roads, covering a conservatively estimated 15,000 miles (25,000 kilometers). A secondary system of people’s roads joined villages and districts throughout the Tahuantinsuyu, bringing the total length of roads to some 25,000 miles (40,000 kilometers). Inevitably, in mountainous country, bridges of various construction were necessary. These ranged from simple stone slabs, through small log bridges and “flying foxes,” to rope-and-leather suspension bridges, some spanning chasms up to 500 feet (150 meters) wide. There were even floating bridges made of rope and reeds.

A corollary of the Incan road system was the army of young athletes called chaqsi, who ran in relays between

staging posts (chasqwasi) set at 8- to 15-mile (13- to 24-kilometer) intervals. They carried verbal messages and sometimes goods. For example, the royal court at Qosqo enjoyed fresh fish delivered from the coast over 200 miles (320 kilometers) away. The messenger service was continuous, relays of runners covering up to 300 miles (480 kilometers) a day. Armies were deployed along the roads, officials moved between administrative centers, priests traveled to supervise religious services, pilgrims wound their way to shrines, merchants transported their goods by llama or alpaca caravans, and herders coaxed flocks down from the high country. For these more leisurely travelers, services were provided at large villages called tanpu along the major routes, strategically located at intervals representing one day’s walk, say 25 to 30 miles (40 to 50 kilometers). In the tanpu, lodging, food, and clothing were available for thousands of people at once, because for political or economic reasons, the Inka sometimes would relocate entire populations. These administrative and service centers were as important to the Inkas as the roads themselves; from them, imperial bureaucrats exercised control over the empire. Thus, for example, several centers were established on the royal road at Tambo Colorado and Huanuco Viejo, each with more than 3,000 buildings to house the civil service, manufacturing and warehouse functions, catering for local food shortages, and so on. Smaller settlements were sometimes built at half-day intervals.

At the beginning of the twenty-first century some 14,000 miles (22,000 kilometers) of Inka roads remain discernible, but much of the continuity has gone, destroyed by modern highways, radio masts, or hydroelectric power stations. Tourism also is taking its toll. Progress is inevitable, but measures are being taken to preserve remnants of the Inka Trail. For example, in the 1990s the Machu Picchu Historical Sanctuary commissioned the British company Mountain Path Repair International to produce a sustainable management plan for the road between Qosqo and the spectacular site and to restore the eroded sections.

Industrialized building

2007-07-04T06:21:00.001-07:00

In the second half of the 1920s the modernist architects of Europe, perceiving an urgent need to reform city planning and especially public housing policies, sought to address the social changes resulting from industrialization. At a 1928 meeting at La Sarraz, Switzerland, architects from Austria, Belgium, France, Germany, Holland, Spain, and Switzerland formed the Congrès Internationaux d’Architecture Moderne (CIAM), agreeing that rationalization and standardization were the chief ways to solve the housing problems each country then faced. CIAM reconvened in Frankfurt in 1929 to discuss the pragmatic issue of existenzenminimum—low-cost residential units. That “unit” should replace “house” in its lexicon is an indicator of pervasive socialist thinking; indeed, politics could not be excluded from any debate on urbanism and housing policies. In its Athens Charter, derived in 1933 and published ten years later, CIAM offered modern technology as the generic solution to the urban problems that would be exacerbated by World War II. That is, they called for a new way of building, and that displacement of conventional thinking with a “problem-solving” approach was an architectural feat in itself. Success is a different matter.

It is one thing to theorize, quite another to find real solutions. Designers on both sides of the Atlantic were investigating industrialized construction techniques as a means of making better, affordable housing. As early as 1910 the German architect Walter Gropius advocated the industrial production of interchangeable housing components, and in 1914 Le Corbusier’s Domino house system employed a standardized framework. It was perhaps inevitable that many of the resulting products were mechanistic and austere, emphasizing structure and detail at the expense of esthetic considerations. This new, efficient way of making architecture was grasped as an opportunity to realize the house as “a machine for living in.” The first half of the twentieth century is replete with designs for systems and components, too numerous to include here. Suffice it to identify a few key individuals.

The French blacksmith and steel fabricator Jean Prouvé (1901–1984) began experiments with prefabricated construction in 1925, in partnership with Aluminium Française and the car manufacturers Citroën and Renault. Given impetus by electric welding technology, after 1931 he produced building components and entire prefabricated structures. In collaboration with the architect Eugene Beaudouin and engineer Marcel Lods, Prouvé built a transportable structure for the Rolland Garros Aeroclub in Buc, France (1935), a forerunner of their Maison du Peuple in Clichy (1936–1939). By adjusting its movable floors, sliding partitions, and openable roofs, the Maison could be adapted within an hour to become a covered market,

a meeting hall, or a cinema. In 1945 the French Ministry of Reconstruction and Planning commissioned Prouvé to produce prototype low-cost, mass-produced housing units. Using a technique he had developed with Pierre Jeanneret and Charlotte Perriand in 1939, he designed his “tree” buildings: a folded-steel central portal (erected without scaffolding) carried aluminum roofing, stiffened by profiling and held in place by external “buffers”; wall panels hung as “curtains” from the buffers. In 1951 the twenty-five dwellings were erected as part of an experimental project in Meudon, proof that industrialized houses were economically feasible. The government shelved the scheme. Although the firm was otherwise successful, serving France and her colonies, Prouvé abandoned it in 1953. His biographer John Winter has remarked, “No one can say of industrialized building that it cannot be done, for Prouvé has done it. He has not adapted building to machine processes; he has worked it all out from scratch as if no one had ever built a building before.”

The most influential pioneer in the United States was the architect, engineer, and inventor Richard Buckminster Fuller (1895–1983). Enthralled by the possibilities of technology, Fuller began what he called his Dymaxion investigations around 1927, with a design for an affordable, easily transportable, environmentally efficient, mass-produced house. The structure of the hexagonal house employed aluminum upper floor and roof elements suspended from a central mast. The ground level was open. Proposals for a Dymaxion Bathroom Unit and a Dymaxion Deployment Unit (for Butler Manufacturing Co.) followed in 1937 and 1941. Then toward the end of World War II, Fuller persuaded the Beech Aircraft Corporation of Wichita, Kansas, to underwrite production of the Dymaxion house. Although the materials used in airplanes and the house were similar, the cost of tooling was so high that many thousands of units would have to be made. Fuller resisted suggested design changes, and the partnership was dissolved after only two prototypes of the circular “Wichita” house (1945) had been built.

In 1946 the French government commissioned Le Corbusier to build a prototype of his “vertical city” in Marseilles. The underlying idea was that standardized self-contained housing units could be slid like drawers into a building frame; the result was the Unité d’Habitation (completed 1952), a stack of 340 cramped “superimposed villas” penetrated by internal streets of shops and services. Adored by contemporary students of architecture, the block was and is detested by the people forced to live in it. It should have furnished the designers and providers of public housing with a salutary warning, but it did not and many similar schemes followed.

The inexorable march of industrialization meant that by about 1960 standardized building components had become commonplace, simply through market forces. Some architects accepted the modular dwelling unit as the primary element in larger housing developments. Wherever they were, like their counterparts of thirty years earlier, they linked industrialization, housing, and urbanism.

In London, Archigram briefly and brassily emerged. In 1964 Warren Chalk coined the expression “capsule homes”—it has a similar ring to “units”—prefabricated modular dwellings that could be stacked up to form a tower. Another member of the group, Peter Cook, proposed the Plug-in City (1964–1966), in which self-contained living units could be temporarily plugged into structural towers. The individual house became an anonymous, interchangeable, wedge-shaped pod, with all the ergonomic efficiency and technological sophistication of a space capsule. The main components were to be pressed metal, plastic, or even pressed paper. Thankfully, nothing was ever built.

But Moshe Safdie’s Habitat was. Constructed as a permanent model community along the St. Lawrence River, and as part of the Montreal Expo 67, Habitat employed 354 prefabricated reinforced-concrete modular boxes, measuring 17.5 by 38.5 by 10.5 feet (5.35 by 11.8 by 3.2 meters), to generate 158 dwellings (900 were originally proposed) of fifteen plan types. By ingeniously stacking the units and fixing them with steel cables, Safdie produced a highly sculptural building with pedestrian walkways, small gardens, and decks. The success of industrialized building lies in the number of units produced, and as in so many other cases, the construction costs of Habitat were prohibitive. It is clear that a people’s image of “house” is a cherished and entrenched cultural value, so innovation and the visionary ideas of architects are not readily accepted. This is one of the main reasons for the repeated failure of industrialized building. Others have been cited as inaccurate reading of the market, excessive profit expectations, inappropriate use of materials, and professional inertia. Nevertheless, experiments continued to the end of the twentieth century. American architect Wes Jones designed the Technological Cabins in the High Sierras for two Californian academics, using standard steel shipping containers as the module, fitting them out before transporting them to the site, and assembling them to form the house. A similar approach at De Fantasie in the Dutch new town Almere, in the late 1980s, proved disastrous from a climatic point of view. Also in the United States, Andres Duany and Elizabeth Plater-Zyberk have maintained the link between the manufactured house and its environment by applying New Urbanism principles when assembling units in a Rosa Vista, Arizona, home park. Perhaps the answer lies in the approach taken by architect Deborah Berke, who assembles modular units to create the conventional and familiar spaces of North American house types

Hydraulic boat lifts

2007-07-04T06:20:00.003-07:00

When inscribing the Canal du Centre boat lifts in Belgium on its World Heritage List in 1998, UNESCO commented that they “represented the apogee of the application of engineering technology to the construction of canals.” That holds true for each example described here. The boat lifts exemplify the seemingly limitless mechanical ingenuity of the Victorian Age. The Industrial Revolution, first in Britain and then in the rest of Europe and North America, saw the necessarily rapid growth of inland transportation networks. Although they were soon augmented (and often replaced) by railroads, canals were the main arteries of industry and commerce. Differences in water levels along their length and at their junctions with rivers were normally overcome by building locks. In order to save time, creative engineers developed a hydraulic mechanism known as a boat lift, which could replace several conventional locks. Among the most ingenious devices of the machine age, the boat lift continued to be refined into the early twentieth century. The principle was simple: a boat or barge entered a watertight trough that was raised or lowered by filling or emptying a counterbalancing trough.

It is likely that the first commercial boat lift was built in 1838 on the Grand Western Canal in the English county of Devon. The canal, first suggested in 1768, was intended to link the Bristol Channel on the west coast and the English Channel on the east. Construction did not begin until 1810 and four years later an 11-mile (17.6-kilometer) stretch was completed. Extensions were built, and by 1838 the canal reached as far as Taunton in Somerset. A decade later the Great Western Railway linked Bristol and Exeter, and work on the canal was discontinued. But the boat lift served vessels carrying limestone from Tiverton

in Devon. Consisting of a pair of 30-foot-long (9-meter) wooden troughs joined by chains, it was capable of raising nearly 10 tons (8.14 tonnes) through the 47 feet (14 meters) that separated two sections of the canal.

The most important English model for others in Europe was the Anderton Barge Lift, built near the English salt-producing town of Northwich between 1872 and 1875. It lifted barges over 50 feet (15 meters) between the Weaver Navigation and the Trent and Mersey Canal. Designed by the engineers Edward Williams and Edwin Clarke, the mechanism comprised two sets of connected hydraulic cylinders and pistons, each supporting a 76-by-15-foot (23-by-4.7-meter) boat tank. In order to lift a boat, a little water was released from the lower tank; as the then heavier counterbalancing tank moved downward, the hydraulic system was activated to raise the lower tank, boat and all. The process was augmented by a steam-powered hydraulic pump. The mechanism lasted for about thirty years, but corrosion problems in the hydraulic system led to the construction of a replacement (albeit incorporating several parts of the original structure) between 1906 and 1908. The new lift continued to carry commercial traffic until the mid-1960s and recreational boats until 1982.

Early among the European clones was the lift at Les Fontinettes on the Neuffossée Canal in northern France. Built in 1888 to raise 340-ton (305-tonne) canal boats 43 feet (13 meters) from the River Aa to the canal, it replaced no fewer than five eighteenth-century locks, dramatically reducing the time needed to negotiate the network of inland waterways linking Calais and Dunkerque with the industrial center of Lille. It was replaced by a single modern lock in 1967.

Proposed in 1879, the 17-mile (27-kilometer) Canal du Centre in Belgium’s industrial Scheldt-Meuse-Rhiue Delta integrates Europe’s inland waterways. Because they survive in working condition, four lifts near La Louvière, also based on the Anderton model, are unique among their contemporaries. Each lifts boats through 57 feet (17 meters). The first, with a capacity of 450 tons (407 tonnes), was built around 1889; the remaining 340-ton (305-tonne) lifts followed between 1908 and 1917. In 1999, as part of a long-term program to increase the capacity of Belgium’s major waterways, a single hydraulic elevator was completed at Strépy-Thieu on a new section of the Canal du Centre. It is capable of moving barges of 1,500 tons (1.370 tonnes) deadweight vertically though 243 feet (73 meters)—the highest lift in the world—in tanks that weigh almost 9,000 tons (8,150 tonnes).

Because of growing industrialization in the late nineteenth century, Germany’s River Ruhr needed a transport network for raw materials and manufactured goods. In 1899 the Dortmund-Ems Canal was built to connect North Sea harbors to the Ruhr region. The Rhine-Herne Canal, completed in 1914, linked the Rhine with Rotterdam and Amsterdam. The two artificial waterways are joined by the 45-foot (13.5-meter) Henrichenburg boat lift at Waltrop. Constructed between 1894 and 1899 it was replaced in 1958–1962.

Another early hydraulic lift system was built in the New World: the Peterborough Lift Lock on the Trent-Severn Canal, connecting Lake Ontario with the upper Great Lakes and the West. Completed in 1904 it consisted of two ship lifts—each with a mass of 1,900 tons (1,730 tonnes) and rising 49 and 65 feet (14.8 and 19.8 meters), respectively—within the 4-mile (6.5-kilometer) canal, replacing eight conventional locks.

Hippodamos of Miletus

2007-07-04T06:20:00.001-07:00

The fifth-century-b.c. Greek architect Hippodamos of Miletus has long been known as the “father of city planning.” Although the claim has been challenged by some historians, his contribution (at least in the West) was the notion of ordered city planning, as opposed to the uncontrolled growth of earlier times. For example, fifth-century-b.c. Athens, the dominant Hellenic city, was an undisciplined accretion of houses lining crooked narrow streets and lanes whose routes were determined by the topography around the great Acropolis. Hippodamos has been credited with the introduction of the orthogonal plan—a “gridiron” with streets at right angles dividing the city into the kinds of blocks we are familiar with. His ideal plan was zoned by land use, with blocks reserved for public buildings and open spaces, integrated with the houses to provide a cohesive social, environment.

However, some elements of the Hippodamean city can be found in earlier Greek settlements. For example, the colony of Smyrna, near what is now the Aegean coast of Turkey, was rebuilt in the seventh century b.c. with parallel north-south streets. Therefore, it may have been that Hippodamos simply formalized generally held conventions in his theoretical writings and applied them in the cities he designed.

In Politics, Aristotle remarks upon the Miletian’s long hair and eccentric dress and notes his wide interest in natural philosophy. It was unusual for an architect to discourse upon the best form of government, but that did not prevent Hippodamos from doing so. His theories of physical planning were linked to social planning; clearly he saw the planner’s role not only in terms of functional and esthetic design but also in human organization of religious, civic, and commercial activities. Adopting what today would be called a determinist approach, Hippodamos divided his optimum population of 10,000 into three: artisans, farmers (every Greek city had its agricultural hinterland), and military. Then he divided the city into three parts: one for worshiping the gods, one to support the soldiers, and the third private, the property of the common people. He went further, categorizing laws into three sorts: insult, injury, and homicide. The political scientist Daniel J. Mahoney has commented, “Hippodamos characteristically divided everything—the population, laws, and land—into threes because he wrongly thought that human nature was amenable to mathematical manipulation.” Yet Hippodamos is not remembered for his utopian social views, but for the physical form of his cities. Several have been attributed to him, including his birthplace, Miletus.

The prosperous fortified Aegean port stood on a peninsula at the mouth of the Meander River. Established by the Mycenaeans in the middle of the second millennium b.c., it grew to be one of the largest cities in Anatolia, a commercial center with a population said to have reached 100,000. In 499 b.c. with sister Ionian cities, Miletus rebelled against its Persian occupiers. They responded by razing it. Liberated after the Persians’ defeat at the naval battle of Mycale (479 b.c.), the Miletians rebuilt their city according to Hippodamos’s orthogonal plan: a repeated pattern of identical blocks with wide main streets crossed by minor thoroughfares. The commercial and religious buildings occupied multiple blocks, and all was enclosed by a defensive wall.

Refounded on the site of an ancient city in the mid-fifth century b.c., the smaller port of Priene, north of Miletus, was set out on a Hippodamean grid. Its plan comprised 84 rectangular 120-by-160-foot (37-by-49-meter) blocks, covering 93 acres (37 hectares) and descending toward the sea from the base

of a 1,000-foot (306-meter) cliff on Mount Mycale. The north-south streets were steep, even needing to be stepped in places; the east-west streets, approximately following the contours, were easier to negotiate. Provision was made for city growth within the encircling walls. In the event, the population remained at 3,000 and more than half the enclosed area was never developed. Reserves for public spaces were part of Hippodamos’s plan, and the agora stood upon a central terrace.

Around 450 b.c., Hippodamos was commissioned by Perikles to redesign parts of Piraeus, the port of Athens. It stood less than 6 miles (9.6 kilometers) southwest of the city on a peninsula surrounded by the Saronic Gulf. He rebuilt the original fortified Themistoclean port, by then about thirty years old, with a well-defined grid of broad streets defining long rectangular blocks. His plan gave better access to the three harbors, dedicated respectively to grain vessels, general cargo ships, and the navy. The parallel Long Walls, about 600 feet (183 meters) apart, were completed in 431 b.c. to protect the supply line between Athens and its port during the Peloponnesian War with Sparta.

There are several other attributions. Hippodamos almost certainly had a hand in the foundation of the colony of Thurii in southern Italy around 444 b.c. Very regular orthogonal extensions to the city of Olynthos, in what is now Macedonia, were laid out soon after 432 b.c. But it may be that Olynthos and the much later city of Rhodes (408 b.c.) on the Aegean island of the same name were laid out by others who implemented the Hippodamean form. That easily surveyed orthogonal form continued to be influential and was perhaps modified by the Romans in any number of their colonial towns. It was revived in the fifteenth century as one of the theoretical bases of Renaissance urban design. Much later, the planners of cities in the New World employed the grid: Savannah, Philadelphia, Chicago, and New York City are all evidence of that. So is San Francisco, where its imposition on a hilly site, even if it provides locations for exciting movie car chases, underlines its suitability for little but the flattest terrain.

Hezekiah’s Tunnel - Jerusalem, Israel

2007-07-04T06:19:00.004-07:00

Hezekiah’s Tunnel, an eighth-century-b.c. subterranean aqueduct in Jerusalem, was a magnificent engineering achievement. Teams of stonecutters, working no more than two abreast and using hand tools, cut the 1,730-foot (576-meter) passageway of bedrock, probably in about seven months. Starting from both ends, between 33 and 150 feet (10 and 45 meters) underground, without sophisticated surveying instruments or contact with the surface, they were able to reach a meeting point.

The Canaanite citadel called Jebus stood on a slope that fell away into a deep valley outside the present-day walls of Jerusalem’s Old City. It had a defensible water supply upon which the conquering Israelites were to build, reaching a climax in the reign of

Hezekiah, King of Judah (727–698 b.c.). Jerusalem depended on a single source of water: the Gihon (or Gichon) Spring. Fed from underground streams and hidden in a small cave on the city’s eastern slope, it also irrigated surrounding farmland through canals built along the Kidron creek bed. Archeologists have found evidence of Canaanite fortifications designed to protect the spring. Gihon’s name describes its erratic nature: the Hebrew word means “eruption” or “gushing.” Although reliably producing up to 245,000 gallons (1.1 million liters) a day, the spring would flow profusely for half an hour, then reduce to a trickle for between four and ten hours—longer intervals in summer, shorter in winter.

A response to siege warfare generated the sophisticated water-reticulation systems that culminated in Hezekiah’s Tunnel, one of the great engineering achievements of ancient Jerusalem. Possibly as early as 1800 b.c., the Jebusites were able to reach Gihon from within their walls: a diagonal tunnel, like others in the region, followed a natural rock fissure to a point from which pitchers could be lowered to the spring. Some scholars believe that this was the passageway mentioned in the Bible, through which Joab led King David’s men into the city, which they then overthrew. It is known as Warren’s Shaft, for Colonel Charles Warren, an Englishman who discovered it in 1867. The debate continues over its date and who built it.

The Israelites augmented this basic system in two stages. First, they built the Siloam (Shiloah) Channel, probably during the peaceful reign of King Solomon (970–928 b.c.). From Gihon a part-open, part-tunneled conduit ran south along the Kidron brook to a reservoir in the HaGal (Tyropoeon Valley) at the southwestern corner of Jerusalem, which by then had been extended to what are now known as the Jewish and Armenian Quarters. Sluices along its eastern side had stone gates that could be opened to irrigate the gardens and fields in the valley below.

Ancient Jerusalem’s most extraordinary hydraulic engineering project—perhaps better classified as a civil defense undertaking—was Hezekiah’s Tunnel, discovered in 1838 by the American scholar Edward Robinson. Under the implacable Sennacherib (705–681 b.c.), the Assyrian Empire extended from the Persian Gulf to the Black Sea, and westward to the Nile valley. His father Sargon had overrun the northern kingdom of Israel, and Sennacherib was concerned with consolidating the family conquests. Hezekiah, the charismatic ruler of the relatively puny kingdom of Judah, reassured by the prophet Isaiah that God would protect Jerusalem, stood against the Assyrian might. He stockpiled weapons and extended the city’s defenses by building the 23-foot-thick (7-meter) Broad Wall. And at the first inkling of invasion he had devised a measure that would help his people survive a siege. He planned “to stop the water of the springs that were outside the city [and] closed the upper outlet of the waters of Gihon and directed them down to the west side of the City of David” (2 Chron. 32:30).

Hezekiah’s Tunnel (701 b.c.), still a functioning watercourse almost 3,000 years later, connects the Gihon Spring and the Pool of Siloam (or Hezekiah’s Pool), specially constructed at the south end of Jerusalem, where the king had extended the outer defenses. Thus the Bible calls the pool “the reservoir between the two walls” (Isa. 22). The direct distance between spring and reservoir is about 1,100 feet (330 meters), but the winding tunnel is 1,730 feet (576 meters) long. On average, it is about 3 feet (900 millimeters) wide and varies between 3 and 9 feet in height; in places, it is 150 feet (45 meters) beneath the surface of the hilly city. The fall from Gihon to Siloam is about 6 feet (1.8 meters), that is, a grade of about 1 in 70. The tunnel was excavated by two groups of workers, starting at each end and cutting toward each other through the rock to eventually connect. The Siloam Tunnel Inscription, engraved on one of the walls and found in 1880, celebrated their meeting:

While there were still three cubits to be cut through, [there was heard] the voice of a man calling to his fellow, for there was an overlap in the rock on the right [and on the left]. And when the tunnel was driven through, the quarrymen hewed … each man toward his fellow, axe against axe; and the water flowed from the spring toward the reservoir for 1,200 cubits, and the height of the rock above the head[s] of the quarrymen was 100 cubits.

Intriguingly, the indirect course of Hezekiah’s tunnel penetrated hard rock while missing softer deposits. Several explanations have been offered for its meandering course. Perhaps the diggers followed a sequence of fissures and crevices that pock the limestone under Jerusalem; perhaps they tried to avoid disturbing the tombs of the kings; or perhaps there was a need to continually reorient themselves—evidenced by a number of false starts and the angle at which the two parts meet.

Hanging Gardens of Babylon - Iraq

2007-07-04T06:19:00.003-07:00

The ancient city of Babylon stood on the east bank of the Euphrates River about 30 miles (50 kilometers) south of modern Baghdad. Philo of Byzantium, writing in the third century b.c., listed so-called Hanging Gardens among the seven wonders of the world. Tradition has it that the gardens were built by King Nebuchadnezzar II (ruled ca. 605–561 b.c.) for his wife Amytis, because she missed the mountainous landscape of her native Media. They may have been commissioned by the half-legendary Queen Sammu-ramut (known as Semiramis) some 200 years earlier. Contemporary Babylonian clay tablets intriguingly ignore them amid lucid descriptions of Nebuchadnezzar’s palace and the city and defenses. Neither the Babylonian priest Berossus nor Philo and other Greek writers—the geographer Strabo and the historian Diodorus Siculus—who centuries later described the gardens ever saw them, and no certain traces survive. Some historians suggest they were merely romantic constructs upon accounts of Mesopotamia carried to Greece after the Macedonian conquest in 330 b.c.

The German archeologist Robert Koldewey believed he had found the substructure of Nebuchadnezzar’s gardens around 1899 when he uncovered several unusual vaulted foundation chambers, atypically built of stone, and a well in the northeast corner of the palace. From more recent excavations concentrated on the southern palace, archeologists surmise that they were in another building, hundreds of meters from the river. Because Strabo’s description had placed them close to the Euphrates, other scholars disagreed. There is another possibility.

More recently, the suggestion has been made that the classical writers were confused, and that the gardens were not in Babylon at all, but in the Assyrian city of Sennacherib, Nineveh, which stood on the Tigris 250 miles (400 kilometers) to the north. Nineveh was about 1,800 acres (700 hectares) in area, enclosed by 10 miles (16 kilometers) of 50-foot-high (15-meter) walls. Within and outside its defenses, Sennacherib created lush parks and gardens, full of exotic plants and watered from a complex, system of aqueducts and canals. They are described on a clay prism dating from about 690 b.c. So is the way in which the huge volume of water needed for irrigation was raised to the highest terrace to flow to lower levels through sloping channels. The king had great brass archimedean screws cast (four centuries before Archimedes!) to lift the water from the ample supply. His description matches those of the later writers. For example, Diodorus Siculus portrays a garden (supposedly in Babylon), whose approach “sloped like a hillside” and whose structure rose “tier on tier,” adding that “water machines [raised] the water in great abundance from the river, although no one outside could see it.” Whether the Hanging Gardens existed or not, or whether they were in Babylon or Nineveh, the descriptions were evocative.

Halles Centrales (Central Markets) - Paris, France

2007-07-04T06:19:00.001-07:00

Once described by novelist Emile Zola as the “ventre de Paris” (belly of Paris), Les Halles, situated in a square northeast of the Louvre, was the popular and vibrant market quarter. It was alive during the day with merchants and shoppers and at night with vehicles bringing produce from the French provinces and other Mediterranean countries, night butchers preparing meat for the next day’s business, and inquisitive patrons from nearby restaurants and bars. Originally the market comprised open-air stalls, but between 1853 and 1866 a series of pavilions was built to create a covered market of grand scale. Known as the Halles Centrales and designed by architect Victor Baltard (1805–1874) with Felix-Emmanuel Callet (1791–1854), the project was commissioned by Emperor Napoléon III as part of the mid-nineteenth-century remodeling of Paris planned by Baron Georges-Eugene Haussmann.

Influenced by his experience of “modern” life in London, Napoléon III was intent upon establishing Paris as an imperial city capable of exploiting new developments in industry, trade, and transport. He aimed to improve housing conditions, remove slums (home to many of the insurgents of the French Revolution of 1789 and nineteenth-century uprisings), establish public parks, and construct grand streets, public buildings, and monuments. The gigantic Halles Centrales was an iron-framed complex that became the prototype for covered market buildings in France and elsewhere, just one of many new structures that emerged during the “Haussmannization” of Paris.

Baltard’s first design was for a classical building with masonry walls. However, the emperor requested that he use iron instead, as a demonstration of France’s industrial prowess. Pressure from a public wanting a spacious, well-lit, and well-ventilated structure forced the architect to adopt a design not unlike the railroad sheds of the 1830s and 1840s. He planned a series of rectangular pavilions laid out in a grid pattern and connected by broad streets, all but one of which was covered. Initially there were six pavilions, but the number was soon extended to ten; a further two were added in 1936. Based on a

19-foot (6-meter) module, they measured either 137 by 197 feet or 197 by 197 feet (42 by 54 meters or 54 by 54 meters). At one end of the long axis there was a rotunda, near to which were the administration and public services. A vast basement housed food stores and such facilities as a butter-mixing room and poultry abattoir, Externally the building frame comprised hollow cast-iron columns, which acted as downpipes for rainwater; they were connected by arched girders. The interior columns, also of iron, supported clerestory walls that rose above the eaves of the pavilions. All was covered with a glazed roof. The infill walls were usually single-skin brick, with stone dressings at the top and bottom; above them were horizontal bands of timber-framed opening windows and fixed louvers.

Between 1962 and 1969, the food markets were moved to Rungis, south of Paris. The Halles Centrales site was earmarked for renewal, and while debate raged over how it would be utilized, its former pavilions were home to exhibitions and other cultural events. In the early 1970s ten of the graceful buildings were demolished; two others were dismantled and reassembled, one in Nogent-sur-Marne, France, and the other in Yokohama, Japan. Les Halles was replaced by the Forum des Halles, an underground métro station with a regional railroad link (1977) and a multistory shopping center (1979). Popular opposition to the demolition of the Halles Centrales led to a wider movement for the conservation of France’s nineteenth-century industrial heritage.

Hagia Sofia - Istanbul, Turkey

2007-07-04T06:18:00.000-07:00

The great Church of the Holy Wisdom, known as Hagia Sofia or Sancta Sofia, in Istanbul, is the high point of Byzantine ecclesiastical architecture, remarkable for its revolutionary dynamic structural system and the ingenuity of a plan that subordinates liturgy to form. It was dedicated by the Byzantine emperor Justinian in December 537. Like many churches, it was built on the site of former sacred structures, some of which predated Christianity. The earliest church had been replaced in 361 by the timber-roofed basilica Megala Ekklesia. Damaged during religious riots in 404, this second building was restored eleven years later under Emperor Theodosius II, only to be burned down in another uprising in 532. Within weeks Justinian commissioned the great church of Hagia Sofia.

He had been, crowned in 527. Despite the fall of the Western Empire to Germanic invaders in the late fifth century, Justinian ensured that his Eastern Empire survived. He and his wife, Theodora, reigned as unofficial joint rulers, together transforming Constantinople into a city that was universally admired and envied. Justinian employed the architects Anthemios of Tralles and Isidor of Miletus to build a church of great size and magnificence, sparing no expense. Materials were transported from all over his domain. Dressed marble was plundered from classical pagan buildings; it is said that eight red porphyry columns were brought from the Artemiseion at Ephesus; new stone came from the finest marble quarries in Phrygia, Egypt, Thessaly, and the Morean Peninsula. The interiors were decorated with mosaics of gold, silver, glass, marble, and granite tesserae. Because of the urgency, tradition has it, 1,000 masons and 10,000 apprentices worked on the building. It was completed in just twenty days under five years. There is a story, perhaps apocryphal, that upon, first visiting the completed church Justinian exclaimed. “Oh Solomon! I have excelled you!”

The central dome, framed with forty brick ribs, is slightly elliptical, its base measuring 101 by 104 feet (30.3 by 31.2 meters). It springs from pendentives at 183 feet (54 meters) above the floor and rises to 226 feet (67.8 meters). There is a window between the bases of each pair of ribs, and the resulting ring of light creates the illusion that the dome is poised in the air with little apparent support. The true massiveness of the masonry structure is replaced with a virtual building created from light—not only because the penetrating rays of the sun constantly change in angle and direction, but also because of the scintillation of the mosaic-covered surfaces as the light skips from facet to facet.

Awesome in size and opulent in finish though it was, it is not for these reasons that Hagia Sofia is an architectural feat. It is because of its structural brilliance and the subtlety with which the spaces are articulated—underlining the difference between the practical directness of Western architecture and the nuances of oriental. Nevertheless, the church remains Roman. The subdivision of its spaces according to their purposes coincides with contemporary Western basilicas: atrium, narthex, nave and aisles, sanctuary, apse, vestries, and altar are all present.

There the similarity ends. Western churches were long and narrow, and their slender parallel walls supported timber-framed roofs. The plan of Hagia Sofia is almost square, approximately 250 by 220 feet (75 by 67 meters), and the four massive piers, each about 25 by 60 feet (7.6 by 18.3 meters), carry a domical roof. Yet when the spatial arrangement of the church is considered, it can be readily seen that by the use of elegant screens to separate aisles and nave, and the placing of the apse, the architects skillfully manipulated a vast single space to meet the liturgical program of the clergy. The interior space is made cruciform by projecting a large hemidome over the apse and smaller ones above the aisles. This daring experimentation with space was made possible through the use of the pendentive, a structural device that allowed Byzantine architects to satisfactorily roof a cubical volume with a dome. That had never been achieved in the West, and never before on such a scale in the East, from whose vernacular architecture it had been drawn.

Hagia Sofia has undergone many changes in its 1,500-year lifetime, with both natural forces and desecration taking their toll. The church was structurally damaged by earthquake only a year after its dedication, and again in 557 and 559. In 562 it was restored and reinforced by Isidoros, nephew of the original architect, who also raised the dome by about 20 feet (6.25 meters). Further earthquake damage in 869 and 889 closed it for five years. The Iconoclasts vandalized the original mosaics in the eighth and ninth centuries, but most were replaced. Hagia Sofia’s finest ornaments were plundered by the Fourth Crusade in 1204, and the building was seriously damaged. Large buttresses were added to the north and south facades in 1317, but that did not prevent considerable earthquake damage about thirty years later. Mehmet the Conqueror took Istanbul for Islam in 1453, and Hagia Sofia, although retaining its name, was put to use as a mosque. Large timber medallions with Koranic texts were hung on the walls of the interior and the Christian mosaics whitewashed over. Minarets were added at various times during the Ottoman period. The building became a museum in February 1935.

At the end of the twentieth century Hagia Sofia stood on the United Nations World Heritage Watch List, one of the world’s 100 most threatened buildings. “Despite … ongoing support, including a grant [$100,000 in 1997] from American Express, water penetration, tourist control, and uncertain structural conditions remain threats. Areas of the lead roof have cracked, roofing members have weakened, and leaks are damaging frescoes and mosaics.” Restoration and repairs of the roof have been effected, but more money is needed to prevent further structural damage and to install a long-term dilapidation monitoring system.

Hadrian’s Wall - Northumberland, England

2007-07-04T06:17:00.002-07:00

The most audacious building project among many initiated by the Roman emperor Publius Aelius Hadrianus (known as Hadrian) was the defensive rampart across the entire width of Britain that marked the northern frontier of the Roman Empire for almost 300 years. Started in a.d. 123 Hadrian’s Wall was about 73 miles (118 kilometers) long, stretching from what is now the town of Wallsend (Roman Segedunum) on the River Tyne in the east to modern Bowness (Roman Banna) on the Solway Firth in the west. From there, seaward defenses, somewhat less substantial, turned south along the Cumberland coast for another 40 miles (65 kilometers).

Spurred by his conquest of Gaul, Julius Caesar undertook a reconnaissance of Britain in 55 b.c. A full-scale Roman invasion took place in a.d. 43, when Claudius was emperor, and there followed decades of resistance by various local tribes. But Britain, soon known as “the food basket of Rome,” was too rich a prize to surrender. Under the governor Petilius Cerealis, the legions marched north into the territory of the Brigantes and established a base at York (Roman Eboracum) in a.d. 71. About ten years later, they pushed forward into Scotland, creating a temporary frontier between the Rivers Forth and Clyde. They intended to consolidate their new conquests by constructing roads and forts (caestra), but the northern tribes proved too warlike, causing the Romans to strategically withdraw.

Hadrian, the adopted son of Trajan, reigned from a.d. 117 until 138. He loved to build: among his architectural schemes in and near Rome were his own tomb (later known as the Castel Sant’ Angelo), the Pantheon, and a luxurious country villa at Tivoli. He was also an inveterate traveler and for over half of his reign he was away from Rome, mostly touring the eastern provinces and North Africa. On a visit to Britain in 122 he appointed a new governor, Aulus Pletorius Nepos, and in order to establish a presence in the far north, he commissioned the construction of the Wall to “separate the Romans from the barbarians.” Work started the following year. As planned, the eastern sector between Wallsend and the River Irthing was to be a stone structure, about 10 feet (3 meters) thick and 15 feet high to the rampart (the parapet was 5 feet higher). As it was eventually built, the thickness along the wall varied; faces were of dressed stone and the infill of rubble. From Irthing to Bowness a turf-and -timber wall, about 20 feet (6 meters) thick at the base, was initially built and replaced with stone within a few years.

Immediately south of the wall—except in the craggy terrain across the Pennines—there was a continuous ditch (Roman vallum), 10 feet (3 meters) deep and 20 feet wide at the top, with a flat bottom 8 feet (2.4 meters) wide. It was flanked, 30 feet away on each side, by wide earth mounds. These earthworks defined the southern limit of the military zone—in effect, like a customs zone at any modern border.

It was originally intended that the wall would be manned by patrols from small forts called “milecastles” at 600-foot (184-meter, the Roman stadium) intervals. Military and logistical backup would come from established but widely spaced fortresses like Corbridge (Roman Corstopitum), usually at the junction of principal roads. Plans changed during the eight years taken for the building. A total of seventeen forts, some for 1,000 foot soldiers (e.g., Housesteads, Roman Vercovicium) and others for elite, 500-strong cavalry regiments (e.g., Chesters, Roman Aesica), were built at roughly evenly spaced locations along the wall. Each milecastle, serving as a controlled crossing place to the north, had a gate reached by stone causeways across the vallum. Each housed only about two dozen men. Between them, Hadrian’s Wall had two evenly spaced stone observation and signal turrets that were manned by legionaries from the milecastles. Construction was practically complete by a.d. 130, although some work seems to have continued for another eight years. Most of the labor was provided by ordinary soldiers of the three Italian legions then based in Britain, who moved about 1.7 million cubic yards (1.3 million cubic meters) of turf and stone.

The total garrison probably numbered about 12,000, mostly drawn from auxiliary legions raised

in different provinces of the empire. It is clear that such a well-manned outpost was not intended merely for defense; it was used to attack the hostile northern tribes. Moreover, Hadrian’s Wall identified Rome by creating a highly visible boundary. Because traders had to use the milecastles as crossing points to the unconquered territories beyond, and because there was a concentration of population, markets and other social structures developed in some areas. Hadrian was succeeded by Antoninus Pius, who in a.d. 139 commanded another advance into Scotland, reestablishing the frontier. The 37-mile-long (59-kilometer) Antonine Wall was built around a.d. 142 between what is now Old Kilpatrick on the Clyde River and Carriden on the Forth. The 9-foot-high (2.75-meter) turf-faced soil rampart stood on a stone foundation. There was a 40-foot-wide (12-meter) vallum, 12 feet (3.7 meters) deep on its north side. Small forts were located at about 400-yard (370-meter) intervals.

By about a.d. 155 the Romans again retreated from Scotland, to return only briefly between a.d. 159 and 163. Hadrian’s Wall regained its former importance; the vallum, which had been partially filled, was finally reconstructed by about a.d. 208. Breached only three times during the remainder of the occupation—in a.d. 197, 296, and 367—it was retaken on each occasion and rebuilt where necessary to remain the frontier of Roman Britain until the last legions departed in a.d. 410.

Great Wall of China

2007-07-04T06:17:00.001-07:00

The largest man-made structure in the world, the Great Wall once stretched more than 4,500 miles (7,300 kilometers) from the Jiayu Pass in Gansu Province in the west to the mouth of the Yalu River in Liaoning Province in the east. The ravages of time and vandalism have reduced it to 1,500 miles (2,400 kilometers). It has been called an “engineering marvel of stone, earth and brick.”

From 475 to 221 b.c., there were seven warring states in Chou dynasty, China—Qi, Chu, Han, Wei, Qin, Yan, and Zhao. The borders of the latter three were frequently plundered by the nomadic Xiongnu (Huns) and Donghu tribes, so they built high earth walls as a defense against them. For their part, the remaining states took similar action, fearing attacks from their capricious neighbors. Soon after he had unified China in 221 b.c., the first emperor, the despotic Ch’in Shi Huangdi, set about reinforcing his defenses against the Xiongnu by joining four earlier fragmentary walls and building new sections to extend them to 3,100 miles (5,000 kilometers). In 214 b.c. he sent General Meng Tien, with an army of 300,000 conscripted workers and countless prisoners, to the northern frontiers of his empire to begin the building the Great Wall. Garrisons of soldiers along the wall served a double purpose: they stood guard over the workers and defended the northern boundaries. Much of the Ch’in wall was constructed with dry-laid local stone, but in remote places, where stone was unavailable, the builders used earth, compacted in 4-inch-thick (10-centimeter) layers. Watch-towers were spaced two bow shots apart.

Ch’in Shi Huangdi’s policies of heavy taxation and forced labor to pay for foreign wars, the Wall, and other extravagant public works inevitably created social unrest. When he died in 210 b.c., his empire collapsed. Following years of chaos, the Han dynasty (206 b.c.-a.d. 220) was founded. Under Wu-Di (reigned 140–87 b.c.), the Han expanded into southern China, Vietnam, and Korea and opened trade routes through the wilderness of central Asia to India, Persia, and the Western world. Wu-Di controlled the Xiongnu incursions by invading their lands south of the Gobi Desert and colonizing the region with his own people. That strategy, incidentally, forced the Huns to move westward, part of a chain reaction that eventually brought about the demise of the Roman Empire. To protect what he had gained, Wu-Di inaugurated the third major phase of the Great Wall. He restored the Ch’in wall—neglected for years, the

earthen parts had begun to collapse—and extended it 300 miles (280 kilometers) across the Gobi Desert. Han builders corrected the problem of the sandy soil by reinforcing the compacted earth with willow reeds. They also built beacon towers at 15- to 30-mile (25- to 50-kilometer) intervals and used smoke signals to warn of attack. All trade routes passed through the Wall.

The final construction phase, which gave the Wall its present form, was undertaken early in the Ming dynasty (1368–1644). Having finally expelled the harassing Xiongnu and their Mongol rulers, the Ming emperors set about securing their empire. They repaired and enlarged the Wall, constructing extensions of tamped earth between kiln-fired brick facings across some of China’s most mountainous terrain. The Ming wall averaged 25 feet (7.6 meters) in height; it was 15 to 30 feet (4.5 to 9 meters) thick at the base, sloping to 12 feet (3.7 meters) at the top. The watchtowers were redesigned and cannon, bought from the Portuguese, were strategically deployed.

For all its size and splendor, the Great Wall seems to have been a functional failure, with little military value. Only when China was weakened internally were northern invaders—the Mongols (Yuan dynasty) in 1271 and the Manchurians (Qing dynasty) in 1644—able to seize power without engaging in an attenuated war. Since the seventeenth century parts of the Great Wall have been quarried for their brick or stone; others have simply crumbled, while those in marshy areas have been buried by silt. Two stretches—the Badaling and Mutianyu sections—north of Beijing have been reconstructed and opened as a tourist attraction. In 1979, the Chinese government declared it a National Monument, establishing a commission to oversee its preservation; in 1987 it was inscribed on UNESCO’s World Heritage List.

Great Pyramid of Cheops - Giza, Egypt

2007-07-04T06:15:00.002-07:00

Giza, Egypt

In the western suburbs of modern Cairo, 130 feet above the Nile, stands a 1-mile (1.6-kilometer) square artificial rocky plateau called Giza (El-Jizah) by the Arabs. It is the site of three Fourth Dynasty pyramid tombs—Cheops’, Chephren’s, and Mycerinus’s—named by the ancients among the seven wonders of the world. The largest of them, built at the command of Cheops, has been called a “unique monument” because of its internal disposition. While it is clearly part of an evolving architectural type, there is little doubt that in terms of engineering and logistics, this so-called Great Pyramid was a superlative achievement.

Cheops, also known as Khufu (Khnum-Khufwy, “Protected by Khnum”), was the second king of the Fourth Dynasty and reigned from 2589 to 2566 b.c. Although little is known of him, he is believed by some scholars to have been a tyrannical and cruel ruler. Whatever the case, clearly he was able to lead and coordinate, because the building of his tomb involved sophisticated social planning to harness an immense team of workers, both on and off the site, together with all the backup resources needed for such a daunting task. The fifth-century-b.c. Greek historian Herodotus calculated that 100,000 slaves would have taken 30 years to build the Great Pyramid. But it was not constructed by slave labor; rather,

Egypt’s peasant farmers, displaced from July through November when their fields were inundated by the annual flooding of the Nile, were deployed on the project, as well as on other public works. The cost of their food and shelter (there were workers’ villages built nearby) was met from their own surplus production, levied as taxes. Modern scholarship suggests that only 20,000 men could have completed Cheops’ tomb in only 20 years.

The base of the Great Pyramid (Akhet Cheops, the Horizon of Cheops), oriented within 0.3 minute of accuracy to the cardinal compass points, is 756 feet (230.5 meters) square, covering 13 acres (5.2 hectares). The extensive base means that the tremendous weight of the tall 479-foot (146-meter) building, amounting to an estimated 6.99 million tons (6.35 million tonnes), does not overload the foundation; it is also very stable because its center of gravity is very low. Although of simple design, such an engineering feat challenges even the modern imagination. The pyramid is estimated to contain 2.5 million limestone blocks, each weighing anything from 3 to 17.7 tons (2.5 to 15 tonnes), rising in 200 steps to the height of a 40-story office block. The joints between the blocks are about 0.02 inch (0.5 millimeter). As originally designed, the pyramid was encased in a 16-foot-thick (5-meter) layer of polished white limestone won from the quarries at Tura, east of the Nile. Most of it was plundered in the sixteenth century and used to build mosques in Cairo. At the pinnacle of the Great Pyramid there was a solid capstone of polished Aswan granite, standing on a 33-foot (10-meter) square platform.

All this, from quarrying to setting the stones, was achieved with copper and stone tools. Barges were used to transport blocks from a quarry on the far side of the Nile. How were they raised as the pyramid progressed? It is thought that ramped causeways, lubricated with water, were used to haul the sleds; these may have been built at different levels on each side of the pyramid, or a single ramp may have wound around the whole structure as it rose. While oxen were used to move stone blocks in the quarry, the accuracy demanded on-site required wooden sleds hauled by men, and fewer than ten were needed to maneuver a block into place using wooden rockers.

For all the looming size of the Great Pyramid, its interior spaces are relatively tiny. An entrance passage—not the original—connects with a narrow, 345-foot-long (105-meter) descending passage that leads to a 46-by-27-foot (14-by-8.3-meter) subterranean room, a little over 11 feet (3.5 meters) high. It has been suggested that this was the first location chosen for Cheops’ burial chamber; that was quickly abandoned, probably on theological grounds. From the junction of the two passages, a 129-foot-long (39-meter) ascending passage leads to the outer end of the “great gallery.” From that point, a horizontal corridor gives access to the so-called Queen’s Chamber, vaulted with inclined blocks; a second alternative burial chamber, it was never completed and never used. The 154-foot-long, 28-foot-high (47-by-8.5-meter) great gallery, with a finely crafted corbel vaulted ceiling, leads upward to the final location of the King’s Chamber, built of pink Aswan granite. The chamber still contains the huge red granite sarcophagus that must have been put in place while the pyramid was being built. Above it a series of five relieving chambers distributes the weight of the structure above away from the chamber. There are two shafts sealed at the extremities, through which the king’s ka (spirit) could come and go from the underworld.

Several ancillary buildings were associated with Cheops’ pyramid. Members of the royal family were buried in mastaba tombs, and three small pyramids to the east were probably for his sister-wife, Merites, and perhaps other queens. Nobles and courtiers were interred in the royal cemetery to the west of the Great Pyramid, where there were also funerary temples and processional ramps. All that remains of Cheops’ Mortuary Temple is some of the basalt paving.

Since the early 1990s, there have been serious attempts to preserve the fabric of the Great Pyramid. It was restored in 1992. Recurring salt deposits, cracking, spalling of the limestone, and the appearance of black spots, all resulting from increases in humidity and carbon dioxide caused by large numbers of tourists, necessitated further action. Early in 1998 the building was closed to the public while a more efficient mechanical ventilation system was installed. It changes the air every 45 minutes, employing the original ka shafts from the King’s Chamber as exhaust ducts and drawing fresh air through the access passage. The number of daily visitors has been severely limited and airlines have been warned of a “no-fly” zone above the site

La Grande Arche - Paris, France

2007-07-04T06:15:00.001-07:00

La Grande Arche is the paramount landmark, the crowning monument of Paris’s Place de la Défense. It is the eastern terminus of the monumental Voie Triomphale (Triumphal Way), extending from the Cour Carrée of the Louvre through the Tuileries Gardens and down the Champs-Elysées to the Arc de Triomphe; the axis then continues for almost 4 miles (6 kilometers) along the Avenue de la Grande Armée and through La place de la Concorde to cross the Pont de Neuilly and enter La Défense.

La Défense is dominated by ultramodern geometric office or apartment towers, 30 stories high and more, apparently randomly arranged over a large, paved plane. It also boasts conference centers, an exhibition hall, gardens, and a massive public pedestrian open space, beneath which is Paris’s largest shopping complex, restaurants, and a cinema. It was conceived in 1931, when a competition was held to extend the Louvre–Champs Elysées axis. None of the thirty-five classical revival or modernist entries from French architects was realized. The aim had been to continue the French tradition of innovative architecture but for various reasons, no doubt including the 1930s Depression and World War II, little of the kind was built. In 1951, La Défense was zoned for commercial use, and seven years later a specifically appointed agency produced a thirty-year master plan;

revised in 1964, it provided for twenty towers, each of twenty-five stories. Developers and the public disagreed over taller buildings, but the mediocre development—someone has described them as “all of the postmodernist ‘could-be-anywhere’ style”—emerged as “a forest of towers” of various heights. Finally, a new monument was built at La Défense “as a counterweight for the Arc de Triomphe”: La Grande Arche—innovative architecture par excellence and a daring technical achievement.

The construction of La Grande Arche was among the more controversial and certainly the grandest of President François Mitterrand’s so-called Grands Projets; initiated at a cost of Fr 15 billion (about U.S.$2.2 billion), the program was intended to build a series of monuments that symbolized France’s central place in the world at the end of the twentieth century. A design competition was held in July 1982, and the 424 entries were reduced to a short list of four for a second stage in April 1983. That was won by the Danish architect Johann Otto von Spreckelsen (1929–1987), in collaboration with the civil engineer Erik Reitzel; their scheme was chosen by an international panel of judges for its “purity and strength.” Work began in 1985 in the hope that the building would be completed in 1989 to coincide with the celebration of the bicentenary of the French Revolution. The budget for the project was Fr 2.9 billion (U.S.$420 million). Von Spreckelsen, frustrated by French bureaucracy and dissatisfied with his own design, later withdrew from the project. He died before the building was finished.

La Grande Arche, dedicated to the French concept of Fraternité, is in fact a square arch, a 330,000-ton (300,000-tonne), 352-foot (110-meter), hollowed-out, chamfered cube that houses in its massive legs thirty-five stories of offices, reached by elevators in freestanding transparent shafts. Most offices are occupied by French government ministries, as well as the Fondation des Droits de l’Homme (Human Rights Commission), the World Road Association, and some large private companies. There are also showrooms, a large exhibition hall, and a conference center. The narrower surfaces of the pre-stressed concrete frame building are faced with Italian Carrara marble and gray granite; glass walls facing into the hollow provide daylight to the offices. The imposing structure is rotated very slightly off perpendicular to the grand axis, in order to accommodate the placement of foundation piles. Around its base and under a suspended fabric canopy known as “the Cloud” are fountains and sculptures by famous artists, including Joan Miró.

Grand Coulee Dam - Washington State

2007-07-04T06:14:00.000-07:00

Commenced during the Great Depression, Washington State’s Grand Coulee Dam, on the Columbia River about 88 miles (142 kilometers) west of Spokane, is a monument to engineering prowess and to the resolve of those people who for 23 years fought for its creation. The key to the Columbia Basin Irrigation Project, it provides the region with electric power, irrigation, and flood control and contributes to wildlife conservation. The Grand Coulee Dam is the largest concrete structure ever built in the United States and the nation’s largest hydroelectric facility. Its 550-foot-high (168-meter) gravity-type concrete wall, 500 feet (152 meters) thick at the base, spans a little under 1 mile (1,592 meters) and raises the water surface 350 feet above the former riverbed. Nearly 12 million cubic yards (over 9 million cubic meters) of concrete were needed to build it. Franklin Delano Roosevelt Lake (often simply called Roosevelt Lake), created by the dam, has a 600-mile (960-kilometer) shoreline and extends 150 miles (240 kilometers) to the Canadian border.

After several ruinous years of drought in the Northwest early in the twentieth century, the U.S. Reclamation Service Bureau (now the Bureau of Reclamation) considered pumping water from the Columbia River to irrigate agricultural land in eastern Washington, a region then served by artesian wells. In 1917 an Ephrata attorney named William Clapp proposed an alternative: build a high-level dam on the Columbia and raise water to the Grand Coulee, the 50-mile-long (80-kilometer) natural channel of the old riverbed, thereby opening up more than 1 million acres (403,230 hectares) of irrigated farmland. Rufus Woods, editor of the Wenatchee Daily World, publicized the notion a few months later. In 1919 the Michigan lawyer James O’Sullivan became interested enough to put it before the Reclamation Service, which directed Washington State’s Columbia Basin Survey Commission to include it in a current feasibility study focused on irrigating the basin by gravity canals from the Pend Oreille River. In the teeth of opposition from vested interests connected with the latter scheme, the dam’s protagonists managed to enthuse, among others, A. P. Davis, director of the Reclamation Service. At O’Sullivan’s prompting, Davis suggested that the state commission an objective report from Seattle engineer Willis Batchelor, who in 1921 recommended a dam on the Columbia, 220 feet (67 meters) above river level.

Several years of argument followed. In 1923 George Goethals of Panama Canal fame—apparently a paid prophet—endorsed the canal system, and two years later the federal Columbia Basin Survey Board of Engineers supported his view. But O’Sullivan, Woods, Clapp, and others unflaggingly kept the dam project alive, and in 1927 the U.S. Senate authorized the Army Corps of Engineers, under Major John Butler, to look for possible sites during a 1929 survey of the upper Columbia River. In June the Columbia River Development League was formed with Woods as president and O’Sullivan as secretary. The Wenatchee Daily World became its mouthpiece. Late in 1931 Butler told Congress that a dam was more economical than a gravity canal: besides providing irrigation and flood control, it would raise revenue from electrical energy. O’Sullivan lobbied for authorization, and the Bureau of Reclamation soon recommended development of the project, almost in the form in which it was eventually realized. In 1933 the Columbia Basin Commission was established, and the state of Washington committed $377,000 to the Grand Coulee Dam. Recently elected President Franklin D. Roosevelt allocated $63 million under the Public Works Administration—a New Deal program. Through the Great Depression men and women from all over the United States would find work at the dam site: averaging 3,000, the labor force peaked at 6,000.

Excavation began in December 1933, and seven months later a $29.34 million contract for the foundation work was awarded to MWAK, a consortium formed by Silas Mason Company of New York City; Walsh Construction Company of Davenport, Iowa; and the Atkinson-Kier Company of San Francisco. Such a large undertaking called for a complex infrastructure: high-tension power lines were set up, the Columbia River was bridged, and over 30 miles (nearly 50 kilometers) of railroad and 60 miles of sealed roads were constructed. A contractor’s town, Mason City, and Coulee Dam, a government town, were built at the site. Four years later, a consortium formed by linking MWAK and the Six Companies—Kaiser Construction of Seattle; Morrison Knudsen of Boise, Idaho; Utah Construction; J. F. Shea Pacific Bridge; and McDonald and Kahn (all of San Francisco) and General Construction Company of Seattle—won the $34.4 million contract for the completion of the dam. Their bid was 80 percent of the only other tender.

The proposed height of the dam had been determined by the rather parochial notion that the impounded water should not back up beyond the Canadian border. Then the project’s main reason for being was irrigation—there were more droughts in the early 1930s—and flood control, rather than power generation. The Pacific Northwest had plenty of electricity and there was little prospect of industrial expansion. Therefore the original designs included a 350-foot (107-meter) “low” dam about 3,500 feet (1,070 meters) long, which would bring the water surface to only 150 feet (46 meters) above the river level. Should the demand for power increase, it was intended to later raise the wall. That was flawed thinking. Achieving a tight joint between the two parts of the wall would have been difficult, even dangerous; later changes to the turbines would be costly; and it was more expedient to construct the concrete foundation of a high dam at the start of the project. So, with the approval of Congress, the contracts were redrawn in June 1935 to build the high dam to plans by John Lucian, chief designer of BuRec engineers.

The main dam was completed by 1941 and work commenced on the pumping plant and powerhouses. The entry of the United States into World War II meant dramatic changes in priorities for the dam. Power generation was given first place because the region’s aluminum industry, a large consumer of electricity, was critical to the defense effort. Six generators were commissioned at the Grand Coulee, and two more were borrowed from the incomplete Shasta Dam project in northern California. Soon after the war, construction resumed on the pumping plant and in 1951 the irrigation system was inaugurated. Six huge pumps lifted water through 280 feet (85.6 meters) from Roosevelt Lake to Banks Lake equalizing reservoir in the Grand Coulee. In 1973 two more reversible pump-generator units were installed, followed by another four late in 1983. Feeding more than 300 miles (480 kilometers) of associated canals, and nearly 5,500 miles (8,800 kilometers) of laterals, siphons, and drains, the pumps can fully supply almost 1.1 million acres (about 440,000 hectares) of formerly dry land. They are not yet being used at their full capacity.

The reversible pump-generators installed could of course be used for power generation, augmenting the already remarkable output of the Grand Coulee Dam, whose power production facilities are by far the largest in North America. Two plants, with a total of eighteen generators, were operational by 1951. A third, coming on line in 1975, increased capacity to about 7,200 megawatts. By 1978 the three were producing over 6,000 megawatts, and subsequently additional generators—the total number is now 33—have achieved an output of over 6,800 megawatts.

In the 1950s the American Society of Civil Engineers included the Grand Coulee Dam and the Columbia Basin Project among the seven civil-engineering wonders of the United States. The project has also been popularly and superlatively dubbed “the Eighth Wonder of the World,” “the Greatest Structure in the World,” “the World’s Greatest Engineering Wonder,” and “the Biggest Thing on Earth.”

Golden Gate Bridge - San Francisco, California

2007-07-04T06:13:00.002-07:00

When it opened to traffic in May 1937, San Francisco’s Golden Gate Bridge boasted the longest single clear span in the world, a claim held true for twenty-seven years. The center span, at 4,200 feet (1,285 meters), was three times longer than the Brooklyn Bridge and 700 feet (214 meters) longer than the recently completed George Washington Bridge in New York. Including the two side spans of 1,125 feet (344 meters) and the 90-foot-wide (27.5-meter) road approaches, its total length was 8,981 feet (2,746 meters). Its towers were the tallest, its main cables the thickest and longest, its submarine foundations the largest ever built. Moreover, the foundation piers of the Golden Gate Bridge were built in

the surging currents of the sea and its superstructure was erected across a canyon through which the wind howled at speeds up to 60 mph (96 kph). And all this was achieved without government funding in the midst of a deep economic depression. Against all the odds, the Golden Gate Bridge was a brilliant answer to a whole cluster of “insoluble” problems.

On 5 August 1775 Lieutenant Don Juan Manuel Ayala of the Spanish navy sailed the San Carlos from the Pacific Ocean into San Francisco Bay through the 3-mile-long by 1-mile-wide (4.8-by-1.6-kilometer) strait now known as the Golden Gate (one Captain John Fremont of the U.S. Army Topographical Engineers named it some 60 years later after Turkey’s Golden Horn).

There is a compelling myth that the San Francisco eccentric Joshua Norton, self-styled “Norton the First, Emperor of the United States and Protector of Mexico,” decreed in 1869 that a bridge be built across the Golden Gate. The story may have become confused with his pronouncement of March 1872 ordering a bridge across the Bay between Oakland Point and Goat Island, an idea he probably gleaned from well-publicized current transportation debates. In fact, the possibility of spanning the Golden Gate was first raised in 1872 by the railroad owner Charles Crocker, who naturally wanted to build a railroad bridge. But little more was heard of the matter until July 1916.

James Wilkins, editor of the San Francisco Call Bulletin, began a campaign that provoked City Engineer Michael O’Shaughnessy to seek, nationwide, the opinion of engineers on the project. Most said a bridge could not be built; the objections raised included the width of the strait, persistent foggy conditions, high winds and ocean currents, and not least, the high cost: some forecast $100 million. However, the experienced Chicago bridge builder Joseph Baermann Strauss (1870–1938) believed that a bridge was feasible and that it could be built for under $30 million. In June 1921 he proffered a preliminary design for a railroad trestle with a cost estimated at $27 million. Then he energetically tried to convince local politicians that he was right. Although urban growth and traffic congestion led to an urgent need to cross the Golden Gate, all available state and federal finance had then been diverted to other projects.

In 1922 O’Shaughnessy, Strauss, and Edward Rainey, secretary to San Francisco’s mayor James Rolph Jr., proposed the formation of a special bridge district comprising the twenty-one affected counties to oversee financing, design, and construction of the bridge. The California State legislature passed the Golden Gate Bridge and Highway District Act in May 1923. In December 1924 the War Department authorized San Francisco and Marin Counties to construct a bridge. Despite opposition from vested interests, the Golden Gate Bridge and Highway District was immediately formed to realize the project.

Eleven engineering firms submitted proposals, and Strauss, assisted by Clifford Paine, was selected as chief engineer in August 1929. Consulting engineers Othmar Amman and Leon Moisseiff, both of New York, and Professor Charles Derleth Jr. of the University of California were appointed. The consulting architects were the husband-wife team of Irving and Gertrude Morrow. Strauss, who had never designed a suspension bridge, first proposed an inelegant cantilever-cum-suspension structure, but Moisseiff, convinced that a simple suspension bridge was possible (although such a span had never been attempted), helped refine the design that was eventually built. The architects did their part, too, designing handrails and light poles, tapering the tower portals, and designing lighting, all to emphasize the bridge’s simple beauty. And, setting aside the conventional paint colors used on bridges, they selected the distinctive “international airways orange” for which the Golden Gate Bridge is famous. That, Irving Morrow believed, would look better in the spectacular landscape and would be more visible in the sea mists for which the Bay Area is noted.

In August 1930 the War Department approved a 4,200-foot (1,285-meter) main span, 220 feet (67 meters) above the sea. Although the United States was sunk in the Great Depression, a $35 million bond issue to finance the bridge received overwhelming popular support. Contracts worth $23.8 million were let in November 1932, and construction started the following January. Over the next four years it proceeded in the face of many natural problems—rapid

sea currents, frequent fogs, and high winds—and technical ones, especially the construction of earthquake-resistant piers in 100 feet of open water. The latter was solved by building elliptical concrete fenders, 300 feet long and 155 wide (92 by 48 meters), within which the 148,000-ton (134,500-tonne) concrete piers could be poured; rising 15 feet (4.6 meters) above high-water mark, the fenders also protect the piers from the onslaught of the sea. The piers and the approach trestles were completed by December 1934 and the 121-foot-wide (37-meter), 750-foot-high (230-meter) towers were standing a little over six months later. The steel sections for the towers, fabricated in Bethlehem, Pennsylvania, were sent via East Coast seaports through the Panama Canal to McClintic-Marshall’s yards in Alameda. Then they were carried by lighters to the site, lifted by cranes, and erected by teams of riggers.

Catwalks spanned the Golden Gate by July 1935, and John A. Roebling and Sons of New Jersey began spinning the two main cables from the San Francisco and Marin anchorages four months later. Each galvanized steel cable is 36.375 inches (920 millimeters) in diameter, comprising 61 strands of 452 wires. They were completed by March 1936, and the roadway steel was placed from June through November, allowing construction of the flexible in situ concrete road deck, finished by April 1937. The bridge was opened to pedestrian traffic on 27 May 1937 and to vehicles at noon the following day. It had been achieved ahead of schedule and under budget. An estimated 200,000 people walked over it on the first day, and a weeklong Golden Gate Bridge Fiesta celebrated the event with fireworks, parades, and other entertainment.

German Pavilion - Barcelona, Spain

2007-07-04T06:13:00.001-07:00

The German Pavilion at the Barcelona Universal Exhibition of 1929, designed by Ludwig Mies van der Rohe, is the first built expression of what he called “the architecture of almost nothing.” About a decade earlier he had designed projects for multistory tower blocks, crystal prisms whose uninterrupted glass skins enveloped slender steel frames. They were just ideas, but the Barcelona Pavilion, as it is popularly known, set a standard—some would say, generated a fashion—for the austere minimalist architecture that would be dubbed the International

Style at an exhibition in New York’s Museum of Modern Art just three years later. Esthetically, it was a major development in modern architecture.

The temporary single-story building, constructed in 1928–1929 and opened in May 1929, exhibited nothing but itself, a pristine, new kind of architectural space. The only purpose it had to serve was brief: to house a reception for the king and queen of Spain when they attended the official opening. For them, Mies designed the now-famous Barcelona chair, handcrafted from stainless steel and covered in white pigskin. The commanding location of the pavilion took advantage of the flow of visitors between the other display halls and the rest of the exhibition. It stood on a low travertine platform that gave a good view of the grounds and beyond to the city. The northern half of the podium was covered by a flat roof, carried on two rows of equally spaced, cruciform steel columns and an asymmetrical series of discontinuous walls of marble, glass, and onyx, parallel or perpendicular to each other. None of the rectilinear spaces thus formed was fully defined—that is, they formed an open plan—and the interior and the exterior of the pavilion were treated in the same way. This was the kind of spatial organization that Mies had observed in the work of Frank Lloyd Wright twenty years earlier. The attention to reductive detail and fine finish was the German’s own. His most often quoted axioms were “Less is more” and “God is in the details.”

A minimalist approach probably was justifiable for the Barcelona Pavilion because the building had no set functional program. It was in essence architecture as sculpture, an end in itself. But Mies also applied the philosophy to more functionally complex buildings. An almost contemporary example was the Tugendhat House in Brno, Czechoslovakia; commissioned in 1927, it was completed in 1930. Then in 1945 he designed a small weekend house in 9 acres (3.6 hectares) of woodland and fields on the bank of the Fox River south of Plano, Illinois, for his mistress, the Chicago physician Edith Farnsworth—a single room partitioned by a core that includes a kitchen, a fireplace, bathrooms, and a service area. The house is a mechanically perfect cuboid carried on a skeleton frame of sandblasted steel channels and defined by 9-foot (2.7-meter) glass walls and concrete floor and roof slabs. Interior finishes include a travertine floor, natural timber fittings, and a stainless-steel counter in the kitchen. Such obsession with refinement, causing Mies to take his architecture of almost nothing almost to the limit, did little to create a comfortable living space. It may have been admirable architecture; it was hardly congenial. It is emphasized that the issue was unimportant in the case of the German Pavilion at Barcelona, which was built simply to be seen and admired—as someone called it, “a place for contemplative lingering.”

When the Barcelona Universal Exhibition closed, the German government tried to sell the pavilion to the municipality, without success. It was taken down in January 1930. It was not until 1983 that the Mies van der Rohe Foundation was established to reconstruct the building in Montjuïc Park, Barcelona, under the superintendence of the architects Cristian Cirici, Fernando Ramos, and Ignasi de Solà-Morales.

Geodesic domes

2007-07-04T06:12:00.001-07:00

A geodesic dome is a fractional part of a geodesic sphere, composed of a complex network of triangles. The archetypal geodesic sphere is made up of twenty curved triangles, each corresponding to one facet of the icosahedron, a twenty-faceted solid geometrical figure. The more complex the network (that is, the smaller the triangles), the more closely the form approximates a true sphere. Using triangles of varying size, a sphere can be symmetrically divided by thirty-one great circles (the largest that can be traced on the surface of a sphere). The triangles form a self-bracing framework that develops structural strength with a minimum amount of material. Thus, the geodesic dome combines the sphere (the most efficient container of volume per unit of surface area) with the polyhedron, which has the greatest strength per unit of mass. Developed in the first half of the twentieth century, it provided a completely new way of building light, transportable structures with efficient thermal and wind-resisting properties. For example, the aluminum-and-Teflon geodesic “Pillow Dome” designed by Jay Baldwin is a permanent insulated structure that can resist 135-mph (216-kph) winds and carry tons of snow; it weighs only 0.5 pound per square foot (2.43 kilograms per square meter).

The world’s first geodesic dome was assembled on the roof of the Carl Zeiss Optical Works in Jena, Germany, in 1922. The 52-foot-diameter (16-meter) structure, designed by Zeiss’s chief designer, Dr. Walter Bauersfeld, was necessary to test what he no doubt regarded as his more important invention, the planetarium projector. He built a complex skeleton of 3,480 light iron rods, accurate in length to 0.002 inch (0.05 millimeter) to form a highly subdivided icosahedron. Twenty-five years later, the American genius Richard Buckminster Fuller (1895–1983) independently derived his geodesic dome (patented 29 June 1954) from general principles, and he is generally credited with the invention of the form.

Fuller was deeply interested in the issues of shelter and housing, and by the end of World War II he had developed industrialized prototypes of the now-famous Dymaxion Houses, which he built for the Beech Aircraft Company in Wichita, Kansas. He then moved his attention to the construction of domes, because he believed that they reflected “nature’s coordinate system” and therefore provided the optimally efficient way to enclose space. Through much of the 1940s he worked on small models of spheres or part-spheres made up of intersecting great circles, just as Bauersfeld had done. Fuller coined the name “geodesic dome” because the arcs of great circles are known as geodesics (Greek, “earth dividing”). In 1948 he seized the chance to take part in the summer school of Black Mountain College in North Carolina, taking with him the material needed to build a large-scale geodesic dome. Applying engineering strategy that he dubbed “tensegrity” (a contraction of “tensional integrity”)—Fuller loved to invent words, too—he devised a system that depended on a continuous tension element rather than “discontinuous local compression members.” He soon built a number of geodesic domes.

In 1953, Fuller built his first commercial dome, for the Ford Motor Company, and it was followed in 1954 by a 42-foot-diameter (12.8-meter) cardboard shelter in his exhibit at the Milan Triennale in Italy; it was awarded the Grand Prize. A few large-scale applications included the Union Tank Car dome (1958). In I960 Fuller proposed a 2-mile-wide (3.2-kilometer), 200-foot-high (60-meter), temperature-controlled geodesic dome to enclose part of New York’s Manhattan Island, claiming that the savings of snow-removal costs would amortize the cost within 10 years. On a more practical level, his domes covered military projects including sensitive radar installations (“radomes”), emergency shelters, and mobile housing. They were and are also used for weather stations, industrial workshops, and greenhouses. One was even proposed for a cinema, in collaboration with the architect Frank Lloyd Wright.

Fuller’s magnum opus is the former United States Pavilion at Expo 67 in Montreal, Canada, designed with Shoji Sadao. The huge, lacy dome, framed with steel pipes enclosing 1,900 molded acrylic panels, has a diameter of 250 feet (76.5 meters) and stands 200 feet (60 meters) high, “weightless against the sky.” It has been adapted by Environment Canada and the city of Montreal and is now known as the Biosphere, an environmental water-monitoring center on the St. Lawrence River.

Gateway Arch

2007-07-04T06:11:00.000-07:00

The 630-foot-high (192-meter) stainless-steel Gateway Arch rises from a wooded park within what became the Jefferson National Expansion Memorial Park on the bank of the Mississippi in St. Louis, Missouri. Taller than the Washington Monument in the national capital and twice as high as the Statue of Liberty, the sleek and seamless Gateway Arch (now known as the St. Louis Arch) is a major achievement of twentieth-century architecture and structural engineering.

A decision was taken in 1935 to establish a national monument in St. Louis, Missouri, to commemorate the nineteenth-century westward expansion that pursued Thomas Jefferson’s dream of a continental United States. A large tract of riverfront land in the older part of the city was acquired and cleared, but the project was interrupted by the country’s involvement in World War II. With the return to peace, in 1947–1948 the Jefferson National Expansion Memorial Association sponsored a design competition for an appropriate monument. The Finnish-American architect Eero Saarinen was awarded first prize.

Work on design development began in 1961, the year of the architect’s death, the project being managed by his firm, Eero Saarinen Associates. Fred Severud of the structural engineering practice Severud, Elstad, Krueger and Associates undertook a feasibility study about the buildability of the daring concept, and Dr. Hannskarl Bandel generated exacting calculations for the weighted catenary (an inverted version of the curve of a suspended chain) that forms the basis of the structure. Bruce Detmers and other architects converted the mathematics into working drawings.

The main contractor was MacDonald Construction, and the steel was fabricated and erected by Pittsburgh-Des Moines Steel. The first concrete pour for the massive 60-foot-deep (18-meter) foundations took place late in June 1962 and construction of the arch itself began eight months later. The span of the arch is the same as its height, and the composite structure consists of 142 welded, stainless-steel-faced sections of equilateral triangular cross sections. The length of their side at the base is 54 feet (16.5 meters), and the sections are 12 feet (3.6 meters) high; at the top, they have a side length of 17 feet (5.4 meters) and are 8 feet (2.4 meters) high. The legs have double walls with an inner skin of 0.375-inch-thick (about 10-millimeter) carbon steel and an outer skin of stainless steel, set 3 feet (90 centimeters) apart; at the 400-foot (120-meter) level, the gap between the skins reduces to less than 8 inches (20 centimeters). For the first 300 feet the space between the walls is filled with concrete; above that, to the crown of the arch, the structure is braced with steel stiffeners. It is clear that the engineering design is highly complicated, but all that can be seen from the outside is the sheer skin of polished stainless steel.

The wall components were fabricated and bolted together in Pennsylvania and transported to St. Louis by rail. On-site, the triangular sections were welded by highly skilled tradesmen. In July 1998 their specialized work was recognized by the American Welding Society’s Historical Welded Structure Award. The completed 50-ton (45.5-tonne) double-walled sections were transported to the site on a specially designed railroad car and lifted into place. For the first 72 feet (21.6 meters), conventional cranes on the ground were used; above that, purpose-made creeper cranes handled the sections. In effect, each leg of the arch was a vertical cantilever and therefore had no need of scaffolding. But when the 530-foot (162-meter) level was reached, a steel stabilizing truss was lifted into place and fixed to brace the two legs while the remaining twenty-one sections and the central “keystone” were located. The arch was completed on 28 October 1965. As the creeper cranes moved back to the ground, their tracks were dismantled and bolt holes in the stainless-steel surface were made good.

In 1967–1968 passenger trams were constructed in the hollow core of the arch, to carry visitors—there were 4 million in 1999—to a 140-person observation platform at the top, where tiny plate-glass windows

give access to views up to 30 miles (50 kilometers) eastward and westward. The total cost of the arch, including $2 million for the internal transportation system, was $13 million. The building received the American Institute of Architects 25 Year Award in 1990.

Galerie des Machines (Gallery of Machines)

2007-07-04T06:07:00.000-07:00

The Galerie des Machines was designed for the 1889 Paris International Exhibition—L’Exposition Tricolorée—by architect Ferdinand Dutert (1845–1906) in collaboration with engineer Victor Contamin (1840–1893). It was remarkable for its vast exhibition hall, made possible by exploiting a new structural innovation, the three-pin hinged or portal arch. Although used previously in bridge construction, this was the first application of the arch on such a large scale.

The concept of exhibiting to the world a nation’s resources and achievements in art, science, and industry has its origins in ancient times. According to the Bible, the fifth-century-b.c. Persian king Xerxes I showed the riches of his kingdom for five months. More recently, fine art exhibitions were mounted, but such shows gradually added inventions. Following the Industrial Revolution and the consequent rise of mechanization, expositions demonstrating industrial progress were held regularly. Before 1900, no fewer than thirteen were organized in the manufacturing centers and capitals of Europe. They were popular events and buildings were purpose-built for them; perhaps the most renowned was Joseph Paxton’s revolutionary Crystal Palace, built in London for the Great Exhibition of 1851. In turn, many of those structures became showpieces of structural and technological advances.

Following the celebrated success of the Great Exhibition and Britain’s abandonment of such shows after 1862, the French seized the opportunity to take center stage, so to speak. Between 1855 and 1900 five international exhibitions were presented in Paris, boasting of the progress of French industry and the country’s rapid transition from a predominantly agrarian to an industrial economy. By 1889 when L’Exposition Tricolorée commemorated the centenary of the French Revolution, the size and variety of machines and other items offered for display were so great that a range of special exhibition spaces was needed. A formal entrance structure was built—the famed Eiffel Tower—and two long galleries were dedicated to the fine and liberal arts and a third to clothing and furniture exhibits. Beyond them and behind the Dome Central that terminated the long axis of the showground rose the vast and impressive Galerie des Machines.

Built principally of iron and glass, the structure employed a three-hinged or portal arch spanning a phenomenal 375 feet (114 meters); the widest previously achieved was 242 feet (74 meters) in the train shed of St. Pancras Station, London, about 25 years earlier. The display hall was 1,270 feet (380 meters)

long, and its colossal proportions provided the largest unobstructed floor area of any building in history—an ideal setting in which to show the world the massive engines, transformers, dynamos, and other wonders of the age. The 20 prefabricated wrought-iron trusses of the main span comprised two half-arches, hinged at their meeting point 143 feet (45 meters) above the floor. They curved and tapered to a slender wedgelike base, where their loads were distributed to the ground through a hinged joint. The apparent lightness with which they touched the ground defied the conventional, rational notion that the base was the principal load-bearing component of any structure; here that role was seemingly reversed. The hinges allowed small movements between the foot of the frames and the foundation but made the arches statically determinate. Thus, stresses and reactions at the supports could be calculated beforehand and were only slightly influenced by movements of the supports or thermally induced dimensional variations.

The iron frame of the galerie was exposed at each end in a frank display of its construction system. The walls were generally glazed, in part with colored glass. Paintings, mosaic, and ceramic bricks also formed part of the cladding. Elevated tracks on each side of the long axis carried mobile walkways above the exhibition space, allowing visitors to travel in carriages and to look down on the machines. The interior was lit by electric lights, invented only some seven years earlier. The galerie was more than just a place for displaying machinery; it was in itself, as one historian has observed, an “exhibiting machine.” It was enlarged for the 1900 Paris Exposition but demolished in 1910, because (so the reason was given) it spoiled the view of the church of Les Invalides. By then, the three-hinged arch was in wide use.

Firth of Forth Railway Bridge

2007-06-23T20:54:00.000-07:00

Firth of Forth Railway Bridge

Scotland

Nine miles west of Edinburgh, Scotland, the mouth of the River Forth is spanned by Europe’s first all-steel, long-span bridge. Completed in 1890 it was then the longest bridge in the world. Until 1917 it was also the largest metal cantilever, and at the beginning of the twenty-first century it remains the second largest ever built. It was a major accomplishment of Victorian engineering.

The extension of the railroad along Scotland’s east coast, to complete the direct route between Edinburgh and Aberdeen, was hampered for most of the nineteenth century by two broad inlets of the North Sea: the Firth (mouth) of Tay and the Firth of Forth. The River Forth rises near Aberfoyle and widens into its firth about 50 miles (80 kilometers) from the ocean.

Vessels up to about 300 tons (270 tonnes) could navigate as far as Alloa, about 16 miles (26 kilometers) inland; those up to about 100 tons (91 tonnes) could reach Stirling, a little further on.

After earlier aborted proposals—a tunnel in 1806 and a bridge in 1818—for crossing the firth, little more was attempted for fifty years. In 1865 an act of Parliament sanctioned a bridge across the Queens-ferry Narrows, where the river passes between steep banks at the neck of the firth. Four railroad companies—North British, North Eastern, Midland, and Great Northern—formed a consortium in 1873 and commissioned Thomas Bouch, engineer for North British, to design the bridge. He proposed a suspension structure with twin spans of 1,600 feet (480 meters). The project was delayed for five years because of lack of funds; by spring 1879 only one pier had been started.

When the much-vaunted Tay Railway Bridge, also designed by Bouch and less than two years old, collapsed in a gale on 28 December 1879 with the loss of seventy-five lives, work on the Forth bridge was immediately suspended by another act of Parliament. In January 1881 a British Board of Trade inquiry found that the Tay disaster was caused by inadequate design and poor supervision. Bouch’s Firth of Forth scheme was abandoned. Within months the engineer died, a broken man. The engineers of the Forth consortium’s member railways, Thomas Harrison, William Barlow, John Fowler, and Benjamin Baker, had to develop a new design. In May 1881 Fowler and Baker submitted a plan for a continuous girder, or balanced cantilever, structure. In July 1882 yet another act authorized construction. The Tay bridge affair had so undermined public confidence in railroads that the legislation insisted that the Forth bridge should “enjoy a reputation of being not only the biggest and strongest, but also the stiffest bridge in the world.” There was to be no vibration, even as trains passed over it. Consequently, it was greatly over-engineered.

Before 1877 steel bridges had been banned by the Board of Trade because the Bessemer conversion process produced steel of unpredictable strength. The Siemens-Martin open-hearth process, developed by 1875, bad changed that, yielding material of consistent quality. That kind of steel was used in the Forth bridge, heralding the transition from cast and wrought iron in such structures. A smaller steel cantilever bridge had been built in Germany, but the Scottish project was on a larger scale than had been seen before. There is little doubt that its designers owed much to a U.S. model of several years earlier. Between 1869 and 1874 James B. Eads had designed and built the world’s first steel bridge, over the Mississippi at St. Louis, Missouri. Its three-arch superstructure, with a center span of 520 feet (156 meters) and side spans of 502 feet (150 meters), supported by four massive limestone piers, carried a railroad and a road for other traffic on two levels. Other pioneering features of Eads’s bridge were adopted by the British: the use of pneumatic caissons (large diving bells fed with compressed air) to excavate the foundation, tubular steel structural members, and a balanced cantilever design that allowed construction to proceed without temporary supports that would have obstructed the waterway.

In December 1882 the contract for the Forth bridge was awarded to a consortium led by Tancred Arrol, an experienced and respected company headed by William Arrol, which already had contracts for the Caledonian Railway Bridge over the Clyde and the replacement Tay bridge. At the height of building activity, there would be 4,600 Britons, Italians, Germans, and Austrians working shifts around the clock. The construction of the foundations and piers took until the end of 1885. Each of the bridge’s three cantilever towers stands on four 70-foot-diameter (21-meter) granite piers, founded on the bedrock. Eight of the piers are in water, and their foundations were excavated by men working in wrought-iron pneumatic caissons, sunk up to 90 feet (27 meters) below the river surface. The massive cylinders were prefabricated in Glasgow, then dismantled and taken to Queensferry, where they were reassembled. Once excavation was complete, the air shafts and the working spaces were filled with concrete, and the granite piers rose above them.

Work on the superstructure began in 1886 using 64,800 tons (54,860 tonnes) of steel from two steelworks in Scotland and another in Wales, fixed with rivets from a Glasgow foundry. All the structural

members were fabricated in on-site workshops, pre-drilled, test-assembled—exact dimensions were needed in a riveted structure—and then dismantled to be painted and carried to the site for erection. Each of the 331-foot-high (99.3-meter) cantilevers consists of two inward-sloping trusses fabricated from huge, internally stiffened tubular members up to 12 feet (3.6 meters) in diameter. They support 680-foot-long (204-meter) cantilever arms that are linked midspan by suspended girders of about half that length, making the distances between the towers about 1,700 feet (540 meters). The length of the bridge between the end piers is about 5,300 feet (1,600 meters). Together with the approach viaducts and arches at each end, the bridge carries the double-track railroad for 2,765 yards (2,490 meters), 150 feet (45 meters) above the surface of the Firth of Forth. The central gap was closed on 14 November 1889, and the Prince of Wales ceremonially opened the bridge on 4 March 1890.

Engineering Building | Leicester University, England

2007-06-23T20:53:00.001-07:00

Engineering Building

Leicester University, England

The Scots architect James Frazer Stirling (1926–1992) formed a partnership with James Gowan (b. 1923) in 1955 after winning a commission for a low-rise housing development in Ham Common, Middlesex (1955–1958). The design started a trend in England for broadly finished brick and exposed concrete. There followed a couple of domestic scale projects, and in July 1959 their more influential work: the Engineering Building at Leicester University (completed 1963), which has been called the “pinnacle of their mutual achievement.” The seminal building, which juxtaposes a glazed office tower with red-tile facings on the massive cantilevered lecture theaters and a single-story workshop, was unlike any postwar architecture elsewhere and broke the hold of Le Corbusier upon British architects. The critic Reyner Banham coined the name “New Brutalism” to describe the new style, which exposed concrete, steel, and brick and rejected the polished and elegant finishes and geometric regularity of the International Modern Movement. The character of the Engineering Building was quickly and widely emulated in Britain; its influence persisted even longer in Japan.

Leicester University was founded as a university college in 1921 and granted its Royal Charter in 1957. The administration appointed the Cambridge engineer Edward Parkes to set up a new engineering faculty, to commence with 200 students. The university also commissioned Leslie Martin to produce a master plan for developing the 9-acre (3.6-hectare) campus; Stirling and Gowan’s building was its first major postwar facility. By the end of 1959 they had produced two alternative preliminary designs. The final scheme was approved in March 1960, although the two architects disagreed over the glazing of the tower block. In fact, their partnership was dissolved as soon as the building was completed.

The building has two main elements: a complex, multistory main building that houses two lecture theaters, laboratories, and offices, and a lower level housing workshops. Two cantilevered reinforced concrete lecture theaters (attributable to the structural engineers), their sloping seating expressed on the outside of the building, are set at right angles to each other and are joined by a diagonal ramp. Four stories of laboratories rise beside the smaller theater on tall concrete columns; surfaces are faced with deep red Accrington brick and red Dutch tiles. Above the larger theater—also brick and tile clad—is a six-story, fully glazed office tower, its narrow rectangular form modified by cut-off corners, crowned by a water tank. The spiral staircase that serves it penetrates the cantilevered block. The adjacent ground-level heavy-machinery workshops, covering over two-thirds of the site and designed mainly by Gowan, are clad in part with translucent glass and roofed with long, diagonal, north-facing glass trapezoidal prisms. One historian has commented that “a mannerist taste for distortion and paradox” permeates the building, and that the “diversity of forms 1/4 is a pretext for the liveliest interplay of masses.” Such a cynical view undervalues the work of one of Britain’s—the world’s—greatest twentieth-century architects; indeed, a winner of the prestigious Pritzker Architecture Prize (1981) and “a leader of the great transition from the Modern Movement to the architecture of the New.”

Empire State Building | New York City

2007-06-23T20:52:00.000-07:00

Empire State Building

New York City

For forty-one years from 1931, the Empire State Building was the tallest tower in the world. That distinction has since been wrested and rewrested by a series of successors. The 102-story building, covering its 2-acre (0.8-hectare) Park Avenue site and soaring to 1,252 feet (417 meters), was completed in the incredibly short time of 1 year and 45 days; in fact, the time from the decision to build to the letting of office space was only 27 months. Because of the precise planning and exacting project management that achieved such efficiency, this most familiar of all skyscrapers is one of the great architectural feats of the twentieth century.

The Empire State Company was formed in 1929 by John Jacob Raskob (General Motors’ chief executive), the industrialist Pierre S. du Pont, the politician Coleman du Pont, Louis G. Kaufman, and Ellis P. Earl. Raskob invited Alfred A. Smith, the New York State governor until 1929, with whom he had political ties, to become president of the corporation. The two men became the prime movers of the project. The 35-year-old Waldorf-Astoria Hotel, on the corner of Fifth Avenue and Thirty-fourth Street, was bought for about $16 million from the Bethlehem Engineering Corporation and demolished to make way for the new building. The architects Richmond H. Shreve, Arthur Loomis Harmon, and William Lamb (who did much of the design work) were initially commissioned to create a 50-story, 650-foot-high (195-meter) office block. But the scheme would go through more than 15 revisions before emerging as an 86-story, 1,252-foot (375-meter) tower. Last-minute revisions would further increase it to 102 floors and a height, including its mast, of 1,472 feet (450 meters). The structural engineers were H. G. Balcom and Associates.

Shreve, Harmon, and Lamb produced a steel-framed, art deco tower whose marble-clad, five-story base covered the whole site. From a 60-foot (18-meter) setback at the fifth floor, it rose uninterrupted to the 86th floor. The upper levels were faced with silver buff Indiana limestone and granite, and the verticality of the facade was emphasized by continuous mullions of chrome-nickel steel. The office floors were served by seventy-three elevators.

The esthetics of the design were hardly remarkable, and the building was either ignored or criticized by the aficionados of the sterile European Modernism—so-called international architecture—then being touted in North America. For the present purpose, the Empire State’s artistic qualities are inconsequential, because its significance lies in the fact that the architects made a design that, in the contractor’s words, was “magnificently adapted to speed in construction.” And speed was of the essence: the clients announced an 80-story building in August 1929 and forecast the completion date: 1 May 1931.

The firm of Starrett Brothers and Eken won the contract, estimated at $50 million. The Waldorf-Astoria Hotel was demolished within a month, and site excavation began on 22 January 1930, digging 55 feet (16.7 meters) below ground to the gray Manhattan bedrock. Construction started just under two months later, and through the meticulous construction scheduling of the chief engineer, Andrew Eken, it proceeded at record pace. Materials suppliers were asked to deliver goods as they were needed, so there was no need for on-site storage in the downtown area. When materials arrived on-site—at the busiest time, that meant almost 500 deliveries daily—they were immediately hoisted to the appropriate floor and transported by railways to their final location for

fixing. The steel frame rose an average of four and a half floors a week, on a forest of 210 steel columns. One fourteen-story section was completed in a week! Altogether, 69,600 tons (58,930 tonnes) of structural steel were placed in only six months. By the middle of November 1930 the building’s masonry skin was fixed. This unprecedented logistical feat was achieved by an average workforce of 2,500, which at times reached 4,000. Together, they worked 7 million carefully monitored man-hours, including Sundays and public holidays, to meet the deadline. In fact, the building was completed a few days ahead of its rigorous schedule. On 1 May 1931 President Herbert Hoover pressed the switch in Washington, D.C., that turned on the skyscraper’s lights.

The Empire State was one of the last gasps of New York’s real-estate boom. From late in the 1800s more than 180 tall buildings, none under twenty stories, had been erected in Manhattan. As that phase was drawing to a close about thirty years later, New York City saw what might be described as a three-sided “skyscraper war.” The antagonists were the Empire State, the Bank of Manhattan, and the Chrysler Building. The “cold and nondescript” Bank of Manhattan, designed by H. Craig Severance and completed in April 1929, was, at 927 feet (278 meters), the world’s tallest building—at least momentarily. The Chrysler Building, then being built for the automobile tycoon Walter P. Chrysler, was originally planned to be crowned with a dome, bringing it to within 2 feet (0.6 meter) of the height of the bank. Its architect William van Alen obtained permission to add the spire that is now recognized as the building’s most distinctive feature. Its components were prefabricated inside the upper floors, and it was placed in just one and a half hours in November 1930, bringing the height of the Chrysler Building to 1,048 feet (314 meters). With the advantage of playing a little behind the game, Raskob and Smith had their architects add six stories to the 1000-foot (300-meter) Empire State Building, originally intended to terminate in a flat observation deck. Above it all soared a 200-foot (60-meter) tower, bringing its total height to 1,250 feet (375 meters).

It was mooted that this tower would serve as a mooring mast for airships. The 86th floor would house passenger lounges, airline offices, and baggage rooms, and the vessels would be moored at the 106th level. One attempt to moor a dirigible succeeded for just three minutes, and a near disaster with a U.S. Navy blimp in September 1931 finally led to the abandonment of the scheme—a decision tragically validated by the fiery destruction of the Hindenberg at Lakehurst, New Jersey, in 1937. The two observation decks remained just that, and the mast later formed the base of a television tower.

The Empire State Building cost $24.7 million. Optimistically conceived during a real-estate boom, the success of the venture was dashed by the Wall Street crash of 1929. When the building was opened its owners were hard-pressed to find tenants for the 2.1 million square feet (199,000 square meters) of office space, and some witty New Yorker coined the nickname “Empty State Building.” Apart from the impact of the Great Depression, the 350 Fifth Avenue address was too far from the central business district. Eighteen months after opening, only a quarter of the space had been rented; six months later, there were still fifty-six vacant floors and the problems continued throughout the 1930s. After World War II the commercial center of gravity of New York was the Rockefeller Center, the last of whose nine towers was completed in 1940. Although the Empire State achieved 85 percent occupancy by 1944, even now it has a vast number of tenants renting small areas. Over 15,000 people work in it, and up to 20,000 clients, shoppers, and tourists visit daily. Every year, over 3.8 million sightseers and tourists visit the observation levels.

In 1955, the American Society of Civil Engineers named the Empire State Building one of the “Seven Modern Wonders of the Western Hemisphere,” and on the occasion of its Golden Jubilee in 1981 it was, not without reason, designated an official New York City landmark.

Eiffel Tower | Paris, France

2007-06-23T20:50:00.000-07:00

Eiffel Tower

Paris, France

The Eiffel Tower was built between 1887 and 1889 as the entrance arch to the International Paris Exhibition, held to celebrate the centenary of the French Revolution. Conceived in 1882 by Gustave Eiffel’s chief research engineers Maurice Koechlin and Emile Nouguier, and constructed in collaboration with architect Stephan Suavestre, the tower is a graceful and imaginative puddled iron lattice pylon. It soars to 1,020 feet (312 meters), the first building in almost 5,000 years to surpass the height of the Great Pyramid.

Preliminary sketches were made in June 1884 and in September Eiffel, suddenly interested in the project, registered a patent “for a new configuration allowing the construction of metal supports and pylons capable of exceeding a height of 300 meters.”

A careful and innovative assembly of over 18,000 small lightweight parts, the Eiffel Tower demonstrated to fullest advantage the structural possibilities of wrought iron. The world’s tallest structure until the Chrysler Building was constructed in 1929 in New York City, it became (and still is) a landmark synonymous with Paris. Intended as a temporary exhibit and scheduled for demolition in 1909, it was saved by its tourist potential and its usefulness as a communication antenna. A radio tower added in 1959 increased its height by 56 feet (20 meters).

Eiffel had specialized in metal construction during his studies at the École Centrale des Arts et Manufactures in Paris. Prior to the acceptance of his design for the tower, he had built in iron and steel, notably the Maria-Pia railway bridge over the Douro River in Oporto, Portugal; the Truyere Bridge near Carabit, France; locks on the Panama Canal; and the internal frame for the Statue of Liberty. Whilst the Parisian tower drew on the outcomes of these projects, it was nonetheless a unique scientific and engineering challenge: its great height meant that wind loads had to be calculated in the design as well as the effects of gravity, Eiffel chose open lattice and splayed legs so that the wind would pass through the structure. In gale-force winds the movement of the tower is estimated to be a mere 4.5 inches (11 centimeters). Speedy and safe transportation of workers and materials (and later of visitors) was another challenge. Eiffel installed elevators that ran on inclined tracks within the tower’s legs; the guide rails were used as tracks for climbing cranes during construction.

The Eiffel Tower weighs over 13,200 tons (11,180 tonnes), more than 70 percent of which is metal. Its 412-foot-square (126-meter) base is defined by the four huge masonry foundation piers set in bedrock; each supports a leg, and the legs converge to form the shaft. Eiffel employed a team of 50 engineers to prepare 5,300 drawings to his specifications, 100 workers to fabricate the components in the Eiffel factory at Levallois-Perret on the outskirts of Paris, and between 150 and 300 site laborers. His calculations were so precise that no revisions were required during construction. Work began on 1 July 1887 and the project was finished in a little over twenty-six months. Eiffel was awarded the French Legion of Honor.

On the tower’s completion, opposition to its erection was silenced. An earlier protest published in Le Temps had been signed by such illustrious Frenchmen as the writers Guy de Maupassant and Alexandre Dumas Jr. and the architect Charles Garnier. Others had described the proposal as a “truly tragic street lamp” and a “carcass waiting to be fleshed out with freestone or brick, a funnel-shaped grill, a hole-riddled suppository.” But it was an instantaneous popular success. In the last five months of 1889, over 1.9 million people visited it. Each paid an entrance fee to help defray the cost—a little under Fr 8 million (about U.S.$1.5 million).

Three viewing platforms—at 186, 376, and 900 feet (57, 115, and 276 meters)—were provided for visitors. At the first, where there were restaurants and a theater, arches linked the four legs; applied after the construction of the legs and platform, they were purely ornamental. Visitors were taken to the first and second platforms in double-deck, glass-enclosed hydraulic elevators. Stairs led to the third platform, and an elevator gave access to the top of the tower, where Eiffel originally had his studio and office (now restored). Each level offered a panoramic view of Paris and beyond for about 50 miles (80 kilometers). From the Eiffel Tower, people were afforded, for the first time, the unique opportunity of seeing the earth from far above.

When the Société de la Tour Eiffel’s original operating concession expired in 1980, the city of Paris assumed direct control of the tower through a company called Société Nouvelle d'Exploitation de la Tour Eiffel. From 1980 to 1984 it undertook a restoration and renovation program. The tower was reinforced in places, 1,560 tons (1,320 tonnes) of excrescences were removed, and the elevators were replaced. It requires regular maintenance, including painting every seven years. The Eiffel Tower continues to be a prime tourist attraction, with over 6 million visitors annually. Each of the viewing platforms is accessible

and Eiffel’s office has been opened to tourists. The exclusive Le Jules Vernes restaurant occupies the second level. During the Paris millennium celebrations of 2000, the tower was covered with thousands of small lights that nightly illuminated the gracious “iron lady” of Paris.

Durham Cathedral | England

2007-06-23T20:49:00.000-07:00

Durham Cathedral

England

Durham Cathedral, built principally between 1093 and 1133 to house the relics of the Northumbrian evangelist St. Cuthbert of Lindisfarne and the Venerable Bede, is the finest example of Early Norman architecture in England. Its significance in the development of Western architecture lies in the use of rib-and-panel vaulting, the pointed arch, and flying buttresses in the gallery roofs—all prophetic of the elegant structural system that we now know as the Gothic.

The cathedral stands in a hairpin bend of the River Wear in County Durham. William I (the Conqueror) selected the naturally defensive site, and by 1072 a castle was commenced on the neck of the steep-sided peninsula to defend the northern region of Norman Britain against the Scots. In 1091 an earlier Saxon church was demolished, and two years later work commenced upon the great building dedicated to Christ and the Virgin Mary. It was to form part of the Benedictine monastery that had been started about a decade before, and the whole precinct soon became the seat of the powerful feudal prince-bishops of Durham. Early in the twelfth century the peninsula was encircled by a wall, much of which survives.

Serious attempts to build “in the Roman manner,” with semicircular stone arches, vaults, and domes—its architecture has been categorized as Romanesque—date from the second half of the eleventh century. The earliest examples saw barrel (or wagon) vaults used in such churches as Santiago de Compostela, Spain (begun 1078), and St. Sernin, Toulouse (begun 1080). These roofs exerted continuous sideways thrust on the side walls, creating the need to build those walls thicker (to prevent overturning); windows were small, in case they diminished the strength of the walls. Sometimes the walls were braced with arches above their piers. Experiments were also made with the Roman cross or groin vault, in which the church was divided into square bays, each of which was covered with a ceiling made by intersecting two barrel vaults at right angles. Although the groin vault transmitted the loads to the walls at equidistant points (thus allowing for thinner side walls with more and larger openings, braced at intervals with massive piers), most of the stress in the vault itself was at its weakest part: the groin. The system can be seen in parts of Durham and in Speyer Cathedral, Germany (originally 1030–1065).

Instead of groin vaults, the nave and choir (ca. 1104) of Durham Cathedral are covered using a revolutionary technique: the bays are framed by lateral, transverse, and diagonal beams or “ribs”—forerunner of the steel- or concrete-framed buildings of modern times—with panels of stone spanning the much smaller areas between them. The most exciting innovation among several at Durham, these are the first known examples of pointed ribbed vaults. The ribs carry their own weight and that of the stone roof to collection points above the piers, and the complex dynamic nature of the loads is thus cleverly resolved. It seems that the northern Italian clerics behind the development of Norman Christianity knew something of ribbed-vault construction, which the invaders took to England. Some sources believe that Lombard experiments may—and only may—have been as early as 1080, but there are certainly no examples on such a large scale as Durham, which therefore preempts by almost a century the key to the dramatic Gothic constructional system.

The church consists of a western galilee, or Lady Chapel; an aisled nave with two western towers; transepts flanking a taller tower above the crossing; and an aisled chancel (which was reduced in length during the thirteenth century). The eight bays of the nave are divided by piers disguised as clusters of columns, alternating with massive circular columns. The same articulation can be found in the choir and transepts. On the face of each pier is a tall shaft rising from the floor that appears to carry the slightly pointed transverse arches that support the vault, nearly 80 feet (24 meters) above. At the triforium (second level), each arch of the arcade is subdivided into two, and on the clerestory (the highest level), arches are supported by a pair of freestanding columns. The nave vault is laterally braced by quadrant arches—heralding the flying buttress of Gothic architecture—concealed in the triforium galleries. The substructures of the 218-foot-high (65.4-meter) central tower and much of the transepts were begun before 1096. The 155-foot-high (47-meter) vault of the crossing, not completed until the fifteenth century, is carried by four huge arches. The original roof of the choir was replaced by the present vault around 1250.

Like many medieval churches, Durham Cathedral has undergone alterations and additions (and, on occasion, what passed for restoration) through almost nine centuries. None has diminished the first impression of overwhelming power and stability experienced by the modern visitor when entering this “fortress of God” at the frontier of the Normans’ domain.

Dover Castle

2007-06-23T20:48:00.000-07:00

Dover Castle

Kent, England

The science of medieval warfare and the design of castle architecture developed side by side until the latter reached its highest degree of sophistication in the almost impregnable concentric castle, exemplified in the royal castle at Dover, known as the “key of England,” the first castle of its kind in western Europe. On a clear day the French coast, 21 miles (37 kilometers) across the English Channel, can be seen from the ramparts above the famous white cliffs of Dover, Europe’s historical gateway to Britain.

In 55 b.c. Julius Caesar landed his reconnaissance force nearby, and following a full-scale invasion in a.d. 43, the Romans built a walled town, Dubris (from which Dover is derived). They built an 80-foot-high (25-meter) flint pharos (lighthouse) on the nearby 375-foot (114-meter) Castle Hill, the site of an Iron Age earthworks that had existed long before. It was inevitable that the commanding position would continue to be used for defense. In the fifth century the Angles and Saxons came in the wake of the Roman withdrawal and founded a fortified town on the hill, employing the ancient defenses. Once Christianized, they built the church of St. Mary-in-Castro (St. Mary in the Fortress) as a chapel for the castle garrison and adapted the Roman lighthouse as part of its bell tower.

William I (the Conqueror) also recognized the strategic value of Dover. He instructed his half brother,

Odo of Bayeux, should the Norman invasion succeed, to land there with building materials for a castle. It took just eight days in 1066 to construct the fortress—probably a motte and bailey—within the Anglo-Saxon earthworks. Nothing of it remains. The motte was an earth mound crowned with a wooden keep and guarded by a wooden palisade; the bailey was a defensible area, also with a palisade and connected to the motte by a bridge. All was surrounded by a ditch. The earliest stone castles were organized in the same way.

Castles multiplied in Britain after the Conquest, responding to the internal tensions created by the feudal system. Dover continued to be strategically important in an international context, a “royal castle” that was not for a feudal baron but for the defense of the realm. Its evolution into a finely tuned concentric castle was a response to changes in medieval military technology and the science of war. Little is known of its earlier defensive works, but extensive rebuilding was undertaken after 1168. Most work was carried out in the 1180s under the supervision of King Henry II’s chief architect, a master mason known only as Maurice. Richard I (the Lionhearted) almost completed it in 1189–1190, and his brother John extended the outer curtain wall at the north side so that the outer bailey had been enlarged to include most of the hilltop. The “completed” castle dates from about 1200. Repairs and extensions were necessary after a siege by rebel barons and their French allies in 1216, during which, despite the collapse of the east tower, it was successfully defended by a force of only 140 knights and men-at-arms. By 1256 Dover Castle reached its maximum strength and size, its outer walls then extending to the cliff’s edge.

Dover Castle, Kent, England; architect(s) unknown, ca. 1168–1200. View showing concentric curtain walls and keep.

Concentric castles comprised a carefully designed keep that was the last line of defense, surrounded by a curtain wall that enclosed a large bailey. Sometimes there was a second, slightly lower curtain wall

(as at Dover) or even a third. Most functions were served by buildings in the bailey. Dover’s daunting keep—the largest in England—was almost 100 feet (30 meters) square and 95 feet (29 meters) high; in places its walls were 21 feet (6.5 meters) thick. It was defended by an inner curtain wall with fourteen projecting “mural towers”—the first in England—which allowed archers to shoot toward any point at the base. The outer curtain wall at Dover was nearly 1 mile (1.6 kilometers) in circumference, with 20 similar towers. Each wall was interrupted only by fortified gatehouses with barbicans. When gunpowder was introduced into the country in the fourteenth century, cannon were developed that could shoot missiles 3 miles (5 kilometers). Given the thickness of its walls, that was of little consequence to Dover Castle. It has been involved in almost every conflict since the Middle Ages. Small wonder it has been called England’s greatest castle.

Changes to artillery were not the main reason for the demise of castles; rather, the feudal system gave place to centralized government and the power of the monarch. In Tudor times, the design of castles was to alter dramatically. As a royal castle, with an eye on the Spanish, Dover was heavily fortified with cannon in the reign of Elizabeth I. It continued to function well beyond that: it was “modernized” during the Napoleonic Wars. Caves were excavated to hide troops waiting in ambush should the French invade. The towers were truncated—some say vandalized—to serve as gun platforms. The caves were again used as headquarters of the Dover Patrol in World War I and as bomb shelters and a hospital in World War II. The castle remained in the hands of the British army until 1958; five years later it was put in the custody of the Department of the Environment (now English Heritage) as a national monument. Conservation work continues.

Dome of the Rock (Qubbat As-Sakhrah)

2007-06-23T20:47:00.000-07:00

Dome of the Rock (Qubbat As-Sakhrah)

Jerusalem, Israel

Jerusalem is a city holy to Judaism, Christianity, and Islam. At its center, the rocky outcrop known as Mount Moriah was the site of three successive Jewish temples, then a sanctuary of the Roman god Jupiter, before it was capped by the Arabic Dome of the Rock, which was for a short while Islam’s most important sacred site. During the Crusades it was commandeered as a Christian shrine before returning to Islamic hands. Today it is at the very core of bitter dispute between Palestinians and Israelis. Although sometimes referred to as the Mosque of Omar, the Dome of the Rock is in fact not a mosque. Nevertheless, as the oldest extant Islamic monument, it served as a model for architecture and other artistic endeavors across three continents for a millennium.

About 1000 b.c. King David of Israel captured the Jebusite town of Urusalim. He renamed it Jerusalem, established his capital there, and chose Mount Moriah—already held sacred as the place where Abraham was prepared to sacrifice his son Isaac—as the site of a future temple. Solomon’s Temple was completed in 957 b.c., only to be destroyed by the Babylonians in 586. The Second Temple was completed by 515 and enlarged and refurbished by Herod the Great (reigned 37–34 b.c.). It was leveled by the Roman legions of Titus in a.d. 70 and has never been rebuilt. The Roman emperor Constantine (reigned a.d. 306–337) decriminalized Christianity in 313. Soon afterward his mother Helena visited Jerusalem, where, according to mythology, she identified the locations associated with Christ, generating a tradition of Christian pilgrimages that continued until the invading Persians destroyed all the churches in 614.

Twenty-four years later Jerusalem was captured by Caliph Umar Ibn al-Khattab, who renamed it Al-Quds (The Holy). Umar cleared the accumulated debris on top of Mount Moriah (Haram al-Sharif) and had a small wooden mosque built on the vast rectangular platform of the demolished Jewish temples.

Dome of the Rock (Qubbat As-Sakhrah), Jerusalem, Israel; architect(s) unknown, 688–692. Restored 1992–1994.

The Dome of the Rock was built between a.d. 688 and 692 for the tenth caliph, Abd al-Malik ibn Marwan. It is an elaborate canopy encircling the bare rock summit of the mount, the sakhra from which Mohammed was miraculously carried through the heavens into the very presence of Allah to receive the tenets of the faith. There is a tradition that, by building the dome, Abd al-Malik was attempting to transfer the Islamic hajj (pilgrimage) to Jerusalem from Mecca, where his rival, Abdullah ibn al-Zubayr, had rebuilt the Kaaba in 684. It is also possible that Abd al-Malik wished to make some tangible statement about Islam’s superiority over Judaism and Christianity, a motive suggested by the form of his building. The Dome of the Rock is more Roman or Byzantine than Islamic, and the caliph’s Byzantine Christian architects employed architectural language understood by Muslims and Christians alike. Because Islamic architecture had not yet established a tradition, they referred to the best Byzantine models, and the congruence in plan and decoration between the Dome of the Rock and the centrally planned church of San Vitale (525–548) at Ravenna, Italy, is not coincidental.

The 60-foot-diameter (18-meter), timber-framed double dome, covered internally with colored and gilded stucco and originally roofed with lead covered in gold, rises 115 feet (35 meters) over the holy rock. It is carried on a tall drum, originally faced with glass mosaics, that rests in turn upon a circular

arcade of twelve Corinthian marble columns, set in threes between four large rectangular piers. At the top of the drum, sixteen colored glass windows light the central space. Surrounding the circle is an octagonal, marble-flagged, 30-foot-high (9-meter) ambulatory of twenty-four piers and columns, reached from outside through four doorways with porticoes facing the cardinal directions. The ambulatory is screened from the sanctuary by half-height walls. The columns and most of the capitals were quarried from older buildings. The marble-faced outer walls of the building also describe an octagon; each side is about 60 feet (18 meters) long. Inside and outside, the Dome of the Rock was enriched with marble columns and facings and floral patterns of mosaic. The total effect must have been awesome: “thousands of lights … supplemented the meagre illumination from the windows, making the mosaics glitter like a diadem crowning a multitude of columns and marble-faced piers around the sombre mass of the black rock surmounted, by the soaring void of the dome” (Ettinghausen and Grabar 1994, 30).

The tolerant Arabian caliphs allowed pilgrims of other faiths access to Jerusalem. Not so the Egyptian Fatimid caliphs who gained control of the city in 969, destroying all the synagogues and churches. In 1071 the Seljuk Turks closed the pilgrimage routes, provoking the Crusades and resulting in the European seizure of Jerusalem in 1099. The Dome of the Rock was converted to Templum Domini, a Christian shrine. The Muslims recaptured the city in 1187, and Jerusalem remained under Islamic control until the nineteenth century.

Although the building has survived in much of its original form, changes have occurred over the centuries. Repairs were made under Caliph al-Mamun (reigned 813–833), and the dome was replaced in the twelfth century; before the successive restorations, its curve was probably slightly horseshoe shaped. More recently, its lead roof has been replaced with aluminum. The glass mosaics that covered the drum of the dome and the exterior walls above the sill line were replaced by ceramic tiles in 1554, when the lower windows were also replaced. In modern times, restorations were carried out in 1924 and 1959–1964. The most recent took place between 1992 and 1994; financed by the late King Hussein of Jordan, it included gilding the dome with 5,000 gold plates and cost U.S.$8 million.

Ditherington Flax Mill

2007-06-23T20:46:00.002-07:00

Ditherington Flax Mill

Shrewsbury, England

The Industrial Revolution gave rise to a new building type: the factory, where a managed workforce could operate machines that were driven by steam power. The advent of machines also created a demand for iron to be produced on a large scale; in addition to being used to build machines, it soon became apparent that iron could be used to construct industrial buildings. The forerunner was the prefabricated cast-iron bridge at Coalbrookdale, England, of 1775–1779. But the factories, especially textile mills, involved problems other than the structural ones. Because they handled large quantities of cotton, flax, and wool, and because their wooden floors were quickly saturated with the oil used to lubricate the machines, they presented a fire hazard. The earliest textile mills had timber floor and roof framing and solid masonry external walls. Cast iron was non-combustible, and it was believed that it offered, as well as greater strength, a measure of fire resistance. Designed in 1795 and built the following year by the

engineer Charles Bage of the milling firm of Bennion, Bage, and Marshall, the Ditherington Flax Mill, in the Shropshire town of Shrewsbury, was the world’s first iron-framed building, the predecessor of most modern factories and even office blocks.

Ditherington was the largest flax mill of its day and one of the largest textile mills of any kind in Britain. The five-story building has conventional load-bearing masonry external walls with very large windows. Internally, it is divided into four bays by three rows of slender, cruciform-section, cast-iron columns, extending for eighteen bays on a north-south axis. Each bay measures about 10 feet (3 meters) square, and the average ceiling height is about 11 feet (3.4 meters). The columns support cast-iron beams spanned by the brick vaults that form the floor above.

The nearby warehouse and cross mill, also iron framed, were built soon after. In 1846 Professor Eaton Hodgkinson published Experimental Researches on the Strength … of Cast Iron, a definitive work that established a design methodology for cast-iron structures; together with Sir William Fairbairn he made a major contribution to the theory of nineteenth-century bridge construction. Cast iron is not fireproof; in fact, it fails structurally and rather dramatically at relatively low temperatures. Consequently, the designers of later iron-framed buildings found ways to protect the columns, often by encasing them in non-load-bearing masonry.

The Ditherington Flax Mill survives, reasonably intact. In 1886 the mill ceased operations, and the building was vacant for ten years. For another century, probably because it had large expanses of open floor space, it was converted to maltings for a brewery. It was empty again from 1987, when the brewery closed down, and has been quite badly vandalized since. In the mid-1990s proposals were put in hand for the refurbishment of all the buildings on the site, with the help of a grant from English Heritage. The project included the creation of shops, restaurants, a heritage information center, leisure facilities and offices, an art gallery, and some housing. In March 2000 Advantage West Midlands announced a £2.8 million (U.S.$4.1 million) grant for the restoration of the mill.

Deltaworks | The Netherlands

2007-06-23T20:46:00.001-07:00

Deltaworks

The Netherlands

The Deltaworks comprises a series of audacious engineering projects that effectively shorten the coastline of the southwest Netherlands by about 440 miles (700 kilometers), seal outlets to the sea, and reinforce the country’s water defenses. Taking more than forty years to complete, the works involved the construction of huge primary dams totaling 20 miles (30 kilometers) in length, in four sea inlets between the Western Scheldt and the New Waterway, Rotterdam.

The Netherlands is located in the broad deltas of the Rhine, Maas, and Scheldt, and the small country’s history and geography have been greatly influenced by a continuous struggle against the rivers and the sea. Through the coincidence of several events in 1953, the southwestern provinces suffered huge floods in which nearly 2,000 people died and thousands of homes were destroyed. The central government quickly reacted, and the Ministry of Transport, Public Works, and Water Management set up the Delta Committee to devise measures to avert a future disaster. The plan informed the Delta Act of 1958, but its implementation, placed in the hands of a complex instrumentality known as Delta Service, took over four decades to complete.

The major elements of the plan were achieved in the following order: the Hollandse IJssel storm flood barrier (1954–1958), the Zandkreekdam (1957–1960); the Veerse Gatdam (1958–1961); the Grevelingendam (1958–1965); the Volkerakdam (1955–1977); the Haringvlietdam (1956–1972); the Brouwersdam (1963–1972); and the Oosterschelde storm flood barrier (1967–1986). The vast scope of the Deltaworks cannot be fully described here, but it may be measured by a brief overview of the largest, most difficult, and most expensive phase: the Oosterschelde (Eastern Scheldt) storm, flood barrier, immodestly referred to by its builders as “the eighth world wonder.”

It was originally intended to close off the Oosterschelde with a permanent dam, and work started in 1967. By 1973 joining das between parts of the coast had closed 3 miles (4.8 kilometers)—more than half—of the river mouth, and three sluices had been built. Then, in response to public protests, it was decided to construct a storm flood barrier instead of completely closing the estuary. Huge concrete pylons standing on the river bottom would support gates that could close to resist storm surges; a concrete roadway would cross the structure. The government signed a contract with the consortium De Oosterschelde Stormvloedkering Bouwkombinatie in 1977. A 3,000-yard-long (2.78-kilometer) access bridge was built to the 50-foot-deep (15-meter)

construction docks needed to fabricate the massive pylons. Commenced in April 1979, the first was finished early in 1983. In the meantime, work began on the sliding gates. Fifty-foot-deep foundations were prepared to support the pylons, and a special dredge was designed to secure the estuary floor against uneven scouring. By the end of 1982, the river bottom was secured by vast mats laid by purpose-designed vessels. All was ready for placing the pylons.

The construction docks were flooded and the pylons, each weighing 21,600 tons (18,300 tonnes) and between 100 and 135 feet (30 and 40 meters) high, were floated into position, then sunk to the prepared floor. Sixty-five pylons formed the spine of the barrier: sixteen in the northern opening, seventeen in the central, and thirty-two in the southern. They were connected by prefabricated elements, and the sliding gates, each 150 feet (45 meters) long and weighing 1,440 tons (1,220 tonnes), were then installed, a task that took a little under two years to complete. Then followed the fixing of each of the sixty-two 3,000-ton (2,270-tonne) precast concrete elements that carried the roadway across the barrier. The Stormvloedkering Oosterschelde was officially opened on 4 October 1986. It cost about a sixth of the 11 billion guilder (U.S.$5.5 billion) total of the Deltaworks.

The danger of overflowing rivers in the winter and early spring also threatens large parts of the Netherlands. Several inland engineering works—the Philipsdam (1976–1987); the Oesterdam (1977–1988); the Markiezaatskade (1980–1983); and the Bathse Spuikanaal and Spuisluis (1980–1987)—were adjuncts to the primary dams of the Deltaworks.

Holland’s struggle against the water continues. Despite the pleas of regional and local water authorities for river dike reinforcement, the national government concentrated its funding for forty years upon the Deltaworks. Moreover, conservationists oppose any dike improvements that would spoil the landscape. The Boertien Commission was established early in the 1990s to address potential problems, and it produced the Great Rivers Delta Plan, which involved reinforcing nearly 190 miles (300 kilometers) of river dikes and embankments. The first phase was completed by the end of 1996; the second, covering another 280 miles (450 kilometers), was finished by 2001. But that will not solve the problem; if nothing else is done, the next generation of Hollanders will have to raise the dikes again. Climate changes, deforestation, urbanization, and drainage in their upper reaches mean that the river systems will carry increasingly large peak volumes. Cooperative policy and water management must be integrated internationally, from the sources to the deltas.

Deal Castle Kent, England

2007-06-23T20:44:00.002-07:00

Deal Castle

Kent, England

Deal Castle, built in 1539–1540 to stand guard over the town of the same name on the Kent coast of southeast England, is a fine example of a new building type, created in response to major changes in politics and the technology of warfare. With others at Walmer and Sandown, it epitomized Henry VIII’s new forts

by its assured and concentrated use of the design elements common to all. Deal is the largest, most impressive, and most complicated of the so-called Device forts. It probably looks just as was intended: crouching in wait low above the beach, stocky, powerful, and seemingly impregnable.

In the turbulent years that followed Henry VIII’s accession in 1509 he twice made war on France, the second time as an ally of the Holy Roman Emperor. Charles V of Spain. When he realized that France’s defeat would give Spain too much power, Henry changed sides, joining France and the pope against the empire. England was financially ruined by the campaigns of 1527–1528, and six years later, Henry’s divorce from Catherine of Aragon led to a break with the Catholic Church, isolating him from most of Europe. He tried to drive a diplomatic wedge between France and Spain, but in 1538 they signed a truce, arousing Henry’s fear of a joint invasion. He urgently launched an ambitious defense program. Using funds plundered from the monasteries by his religious “reforms,” in 1539 Henry initiated a chain of about thirty forts and batteries to defend England’s major ports and repel the expected invasion fleet. They included ten Device forts: Portland, Pendennis, and St. Mawes in southwest England; Hurst, Calshott, and Sandgate around the Solent; and Camber, Walmer, Sandown, and Deal on the southeast coast.

The nature of warfare was changing, and the sophisticated defense systems of medieval castles had become obsolete. Built to resist mechanical artillery, they now had to withstand, missiles shot with gunpowder. The clumsy bombards of the fifteenth century could be fired only a few times an hour. But by the early sixteenth century cast-iron cannonballs had replaced stone; powder quality had improved; and ordnance was generally smaller, reliable, and accurate. In 1386, Bodiam Castle in Sussex was among the first to replace archers’ loopholes with cannon and gun ports. The decline of feudalism also had its effect: enemies were more likely to be foreign than envious neighbor barons.

Finished late in 1540 Deal, Walmer, and Sandown completed the metamorphosis from medieval castle to modern artillery emplacement. Each of these squat, powerful-looking “castles in the Downs”—they were still called castles—comprised rounded bastions radiating from a circular keep. Their thick walls were curved to deflect cannonballs, and their many gun ports were widely splayed for easy traverse. There were three tiers of cannon for long-range offense and two tiers of defensive armaments. Built by an army of workmen at a total cost of £27,000—1,000 years’ pay for an artillery officer—and joined by earthen bulwarks (since vanished), they formed a defensive cluster along a vulnerable 2-mile (3.2-kilometer) stretch of coast. Sandown has succumbed to coastal erosion, and Walmer has been converted to a residence for the Warden of the Cinque Ports. Only Deal, overlooking the low-lying marshlands, has been conserved.

Henry VIII’s sexual notoriety has overshadowed his considerable abilities as a scholar, poet, and statesman. He took an interest in military engineering and personally amended the proposals for his forts, and the “device” (that is, the design) of Deal Castle has been attributed to him. The temptation to compare the concentric plan to the Tudor rose (as many have done), although alluring, must be resisted. Built with stone quarried from a nearby Carmelite priory, the castle’s architectural form was primarily constrained by serious military purpose: to pack the maximum firepower into the most compact possible structure.

Six semicircular bastions, with curved parapets and bristling with gun emplacements, radiate in two tiers from a central, cylindrical barracks-keep; the configuration is repeated in the surrounding moat. The upper tier abuts the tower; the lower forms the curtain wall. The concentric layout allowed ordnance to be effectively positioned and fired simultaneously without impeding each other. Almost 200 openings penetrate the massive walls at five levels, including 119 cannon ports and embrasures. The remaining loopholes and casemates, mostly at the lower levels, were for arquebuses and pistols. Gun positions within the bastions were vented to clear the smoke and gases. It is easy to imagine the withering salvo afforded by such purposeful design, but it has been suggested that Henry was unable to find enough cannon to fully equip his fortresses.

Because architects usually build upon what they know, Deal, simply because it had evolved from the

medieval castle, also employed traditional defenses. The entrance was at second-floor level and approached by a drawbridge across the moat; attackers then faced a portcullis, beyond which there were heavy, iron-studded oak doors. The gatehouse ceiling was penetrated by five “murder holes” (gun slots for small arms), and a cannon protected an inner door. In the manner of earlier keeps, the central tower was self-sufficient: its basement had supply and ammunition stores and a well. The garrison was quartered at ground level, with a mess hall with fireplace and bake ovens. The upper story housed, rather more comfortably, the captain of the guard.

The anticipated Catholic assault never came. Although Deal was again readied in 1588, this time to repulse the Spanish Armada, once more no invasion eventuated. Late in the English civil war the fortress was held briefly by the Royalists, but they surrendered after a sustained bombardment. In the eighteenth century Deal’s parapets were altered (some say disastrously) in unfulfilled expectation of attacks during the French Revolution, and again during the Napoleonic Wars. No shot was fired in anger until the German bombing of 1941. Since 1984 Deal Castle has been in the care of the Department of the Environment (now English Heritage).

De Stijl

2007-06-23T20:44:00.001-07:00

Founded in Leiden, the Netherlands, in 1916, the group known as De Stijl was Europe’s most important theoretical movement in art and architecture until the mid-1920s, when leadership passed to Germany.

In 1916 the architect J. J. P. Oud met the critic and painter Theo van Doesburg and soon introduced him to another young architect, Jan Wils. First forming De Sphinx artist’s club in Leiden, the three founded, with the railwayman-philosopher Anthony Kok and the painters Piet Mondrian, Bart van der Leck, and expatriate Hungarian Vilmos Huszár, the group known as De Stijl. Others joined them: the fiery Communist Robert van ’t Hoff and the Belgian sculptor Georges Vantongerloo (both in 1917); the furniture

designer Gerrit Rietveld (1918); the architect Cor van Eesteren (1922); and the painter César Domela (1924). Later arrivals were balanced by departures.

The first manifesto was issued in November 1918, though not all the members signed it. Therefore, De Stijl should never be thought of as a group in the sense that, say, the Pre-Raphaelites or the Impressionists were groups. The members never reached unity of purpose; there were no meetings; and membership seems to have lain in contributing to De Stijl, a polemical journal jealously conducted by van Doesburg. He stretched and frayed their fragile ties by personality issues, and the whole fabric unraveled as members withdrew one by one, unable to work with him. Van der Leck lasted only until 1918; Wils and van ’t Hoff left in 1919; Oud and Vantongerloo two years later; and Mondrian in 1925. Others briefly established links with van Doesburg, but after 1925 only he was left to continue the magazine, by then published only spasmodically. He died in 1931.

Many De Stijl members were influenced by Theosophical doctrine and, subscribing to a holistic worldview “in which the geometric [was] the essence of the real,” they sought unity within the arts and between art and society. Perhaps because its mysticism, religion, and philosophy offered a palliative for the problems of burgeoning capitalism, Theosophy appealed to many in the industrializing world at the fin de siècle. Socialism was an important factor at the time of De Stijl’s birth and for some members social issues were all. They so concerned van ’t Hoff that, unwilling to work for middle-class clients, he soon forsook architecture altogether. Seeking an appropriate architecture, the others explored Constructivism, temporarily preached Neoplasticism, and generated what Oud called Cubism, but theory seldom extended to architectural realities. The few realized projects were spectacular: van Doesburg’s Café Aubette, Strasbourg (1926–1927, with Jean Arp and Sophie Taeuber-Arp), carried “painting into architecture, theory into practice.”

Rietveld’s Schröder house demonstrated De Stijl ideas and became an icon of European Modernism. In 1921, Rietveld began to collaborate with the interior designer Truus Schröder-Schrader. The tiny house in Utrecht (1924) that he designed for her expresses, more than anything else undertaken by the group, the principles valued by De Stijl. Earlier, Rietveld had collaborated with his De Stijl colleagues on fragments of schemes and unrealized projects. What they had been able to only dream of or explore in scale models, Rietveld built as his first complete architectural work.

The division among Dutch architects on religious and political grounds prevented wider acceptance of De Stijl’s ideas within the Netherlands. De Stijl became an international journal (or rather, by van Doesburg’s duplicity, an illusion of one), and through its pages and his personal preaching he shared with Europe the message of an architectural climax. De Stijl was moribund when van Doesburg died in 1931, but for a moment or two, through it, the Dutch had supplied a lot of theoretical and rather less practical input to modern architecture. Not least, by commenting upon his work to a wide audience, they provided a gateway for Frank Lloyd Wright’s “peaceful penetration of Europe.” In 1936 Alfred Barr of the New York Museum of Modern Art perceptively remarked that De Stijl had overshadowed German architecture and art in the mid-1920s. Moreover, had van Doesburg’s attempted insinuation into the Dessau Bauhaus succeeded, that critically important school of architecture and design would have been turned toward Russian Constructivism.

De Re Aedificatora

2007-06-23T20:43:00.000-07:00

Leon Battista Alberti’s theoretical treatise on architecture, titled De Re Aedificatoria (About Buildings), was dedicated in 1452 but not published until 1485. What qualifies it as an architectural feat? It changed the understanding and practice of architecture in much of Europe and continued to influence developments there and in the New World for about 400 years. Although he was gathering the ideas for the book, Alberti (1404–1472) was not an architect but a Catholic priest.

Alberti was born in Genoa, the illegitimate child of Lorenzo, an exiled Florentine from a family of bankers. When he was about ten years old, Battista (he added “Leon” later) entered a boarding school in Padua to receive a basic classical education. Several years of legal studies at the University of Bologna led to a doctorate in church law in 1428, after which he went to Florence. He soon began writing. His first published anthology of poems, Il cavallo (The Horse) of 1431, was quickly followed by Della famiglia (About the Family)—the first of many philosophical dialogues—and La tranquillità (Composure), a collection of essays, short stories, and plays, both in 1432. By then he was employed as a secretary in the Papal Chancery in Rome and was about to undertake a lives of the saints and martyrs, written, as was fashionable, in classical Latin. Living in Rome opened Alberti’s eyes to classicism, although the city was to remain neglected for another fifteen years. In 1434 he wrote a study about urban design entitled Descriptio urbis Romae (Description of the City of Rome), in which he first explored the classical notion that beauty existed in harmony, achievable through mathematical rules.

Alberti’s future lay not in the law but in the church. Taking holy orders, he would eventually become a canon of the Metropolitan Church of Florence in 1447. Other clerical offices and their benefits followed: abbot of San Sovino, Pisa, Gangalandi Priory, Florence, and the rectory of Borgo San Lorenzo in Mugello. In 1436 he completed his first major book, written in classical Latin, that touched upon architecture: De pictura (About Painting) was an attempt to bring system to perspective and set down rules for the painter to achieve concord with cosmic harmony. An Italian translation appeared in the same year.

From about 1434 Alberti traveled through northern Italy in the retinue of Pope Eugenius IV, visiting Florence, Bologna, and Ferrara, where, in 1438, under the patronage of Marchese Leonello, he began a more careful study of classical architecture, delving into the ten-part book De Architectura, written by one Marcus Vitruvius Pollio around 20 b.c. Alberti returned to Rome six years later and extended that study among the ancient buildings. When Nicholas V succeeded to the papacy in 1447, Alberti was appointed inspector of monuments, an office he held

until 1455. De Re Aedificatoria, written in classical Latin and structured in ten parts like Vitruvius’s De Architectura, was completed in 1452. Vitruvius’s book was its principal source and model, but Alberti also drew upon Plato, Pythagoras, and the Christian fathers; his own archeological studies; and, importantly, the consensus of contemporary architectural thought. Vitruvius had summarized the architectural practice of his day; Alberti went further to lay down universal rules.

As Italian society and fashions changed, from around 1420 the mason-architect had begun to be displaced, first by the artist-architect and then the courtier-artist-architect. With training in neither building nor art, Alberti wrote a book about the art of building that completed the metamorphosis of the architect into a dilettante-scholar; that made “design distinct from matter,” as he put it, and turned the art of architecture into an academic pursuit in which creativity and design skill could be honed to perfection simply by obeying a set of rules. Intuition was replaced with measurable absolutes. It gave architectural design a thoroughly developed theory of harmony and proportion and made it simple—at least in theory. According to some sources, the last Latin edition was a folio version in Bologna, of 1782. Translations and many derivative works found their way through western Europe.

Book I of De Re Aedificatoria defined design, set down the criteria for good architecture (convenience, stability, and delight), and discussed the basis of composition and proportion. Book II dealt with matters of professional practice and building materials. Book III addressed practical building construction. Book IV covered many aspects of civic design, and Book V dealt with plans for various building types. The next book explored the esthetic dimension of architecture, defining beauty as “a harmony of all the parts in whatsoever subject it appears, fitted together with such proportion and connection, that nothing could be added, diminished or altered, but for the worse.” It also included a section on mechanical and technical details. Alberti’s strong attachment to antiquity was revealed in Books VII and VIII, that took up the subjects of ornament in religious buildings and Roman urban design, respectively. In Book IX the axiomatic principle underlying Renaissance architecture was restated: that beauty is an innate property of things, achieved by following cosmic rules. Then there was an assortment of chapters about mostly practical issues. Book X descended to the pragmatic: water supply, engineering, repairing cracks, and even how to get rid of fleas.

Alberti applied his theories in only a few buildings, mostly unfinished renovations or extensions. They included the facades of the Church of San Francesco (otherwise known as Tempio Malatestiano) of 1450, in Rimini; the facades of the Palazzo Rucellai (1446–1451) and Santa Maria Novella (1458–1471), both in Florence; and San Sebastiano (1459) and Sant’Andrea (1470–1472), both in Mantua. His biographer Giorgio Vasari wrote in 1550, “His writings possess such force that it is commonly supposed that he surpassed all those who were actually his superiors in art” and added, “He was a person of the most courteous and praiseworthy manners … generous and kind to all.”

Curtain walls

2007-06-23T20:41:00.000-07:00

Curtain walls

Traditionally, the wall of a building served both structural and environmental purposes. That is, it carried to the ground the weight of the building and its contents and, while admitting air and light through openings, protected the interior from extremes of weather, noise, and other undesirable intrusions. The introduction of structures in which the loads are carried by beams and columns liberated the wall from load bearing, allowing it to function solely as an environmental filter—a relatively thin, light curtain, so to speak. This was first seen in the later medieval cathedrals with their vast stained-glass windows, but it would not be widely developed until the nineteenth century, with the advent of metal-framed architecture and, subsequently, reinforced concrete. The metal-and-glass membrane supported by the building frame, known as the curtain wall, is principally associated with multistory office buildings after about 1880.

Seagram Building, New York City; Ludwig Mies van der Rohe, architect, 1954–1958. Exterior, photographed in 1997.

Although the first skyscrapers, such as the Rookery (1885–1886) and Monadnock Building (1889–1891), both in Chicago and both designed by architects Burnham and Root, had thick conventional load-bearing walls, the twin economic necessities of getting buildings up quickly and optimizing the quantity and quality of interior space soon led to buildings whose outer walls consisted almost entirely of windows supported by perimeter columns and beams. This was a first step toward the development of a true curtain wall, that is, a continuous wall in front of the structural frame. The earliest example was Albert Kahn’s Packard Motor Car Forge Shop in Detroit (1905). A curtain of glass in steel frames allowed more space

and light in the factory, just as it would in an office tower, and Kahn again employed it for the Brown-Lipe-Chapin gear factory (1908) and the T-model Ford assembly plant in Highland Park, Michigan (1908–1909). This rational industrial architecture drew the admiration of Europe and was emulated in Peter Behrens’s A. E. G. Turbine Factory (1909–1910) in Berlin and Gropius and Meyer’s Fagus Works in Alfeld-an-der-Leine, Germany, of 1911.

It is widely accepted that the first office block with a curtain wall was Willis Jefferson Polk’s eight-story Hallidie Building (1917–1918) in San Francisco. Although it was cluttered in places with florid cast-iron ornament, the street facade, suspended 3 feet 3 inches (1 meter) in front of the structure by brackets fixed to cantilevered floor slabs, presented an unbroken skin of glass. Elsewhere, others dreamed of crystal prisms in which the building’s whole external membrane was glass: the serried towers of H. Th. Wijdeveld’s Amsterdam 2000 (1919–1920) and Le Corbusier’s Ville Contemporaine (1922) and—probably best known—the skyscrapers Ludwig Mies van der Rohe projected between 1919 and 1923. But dreams and visions they remained, because the technology was not yet available to turn them to reality. One exception was the A. O. Smith Research Building in Milwaukee (1928–1930) by Holabird and Root, the first multistory structure with a full curtain wall (rather than a single facade) of large sheets of plate glass supported on aluminum frames.

Spin-offs from defense technologies after World War II paved the way for tall curtain wall buildings. Important among them was cost reduction in the production of aluminum, whose corrosion resistance could be improved by a process known as anodizing. This lightweight metal could be extruded into the complicated profiles needed to frame the glass and strengthen the wall against wind loads. Reliable cold-setting synthetic rubber sealants had also become more widely available. These advances were combined with more efficient sheet glass manufacture, especially polished cast glass and, after 1952, the much flatter float glass. Wall elements could be fabricated off-site to exacting tolerances and then transported, assembled, fixed, and glazed with none of the “wet” processes that impede building contracts. Relevant engineering developments included reverse-cycle air-conditioning—available since 1928—and fluorescent lighting, first demonstrated at the 1938 Chicago World’s Fair. All these technologies were exploited in Pietro Belluschi’s twelve-story Equitable Building in Portland, Oregon (1944–1948), described by one historian as “an ethereal tower of sea green glass and aluminum.” Another writer asserts that it “set styles for hundreds that came after.”

The thirty-nine-story United Nations Secretariat Building in New York City followed in 1947–1952. The final design was developed from a proposal by Le Corbusier, and Wallace Harrison acted as executive architect in consultation with him. The curtain walls of the Secretariat Building’s east and west facades are all glass, cantilevered 27 inches (80 centimeters) from the line of the perimeter columns; black-painted glass spandrels hide the between-floor spaces. The blue-green tinted windows are of “Thermopane,” a special glass that absorbs radiant heat, preventing it from reaching the interior, thus reducing the load on the air-conditioning system. The only breaks in the sheer curtain wall are full-width air-conditioning intake grilles at four levels. Because of its innovation, and no doubt because of its associations, the U.N. Secretariat, together with Mies van der Rohe’s Lake Shore Drive Apartments (1951) in Chicago and Skidmore, Owings, and Merrill’s Lever House (1952) on Park Avenue, New York, contributed to the universal standard for high-rise buildings.

The latter building, a twenty-four-story, green-tinted glass and stainless steel tower, designed by Gordon Bunshaft, marked a change of direction in American corporate architecture and in the way New Yorkers built. In keeping with the wishes of a client who made household cleaning products, Bunshaft produced an immaculate, clean-lined tower. The architectural critic Lewis Mumford called it “an impeccable achievement.” The top three floors are reserved for mechanical services. A mobile gantry carries a window cleaners’ platform that serves all faces of the building; such devices became standard for the curtain wall office buildings that followed. Lever House was the first skyscraper to exploit the allowable plot ratios in city planning regulations. By

occupying only a quarter of the site, it allowed much more natural light to enter the offices than conventional stepped-back skyscrapers that covered the whole allotment. Lever House is a New York historic landmark, and in November 1999 a $10.7 million contract was let to renovate its curtain walls, designed by Skidmore, Owings, and Merrill under the supervision of the New York City Historical Society.

That leads us to the inherent problems in curtain wall construction, for all of its advantages. In forty-five years, the pristine facades failed in a number of ways—water penetration and consequent damage, corrosion, and broken glass panels. Since their inception, curtain wall systems have been continually revised, most changes geared toward reducing weight while retaining strength. Stiffened sheet aluminum, enameled steel laminated with insulation, and later even thin sheets of stone were used for spandrel panels. The design of joints—problem spots for leaks—was improved and more durable sealants were invented. More recently, the availability of reliable adhesives has allowed architects to indulge in so-called “fish tank” joints between glass panels, doing away with framing bars. Glass technology has also been refined. Double glazing, first manufactured in the 1940s, improves both the sound and thermal insulation of curtain walls. Heat-absorbing glass, already available in the 1950s, evolved in the following decade into reflective glass with thin metallic coatings, also used to reduce heat gain within buildings. In 1984 heat mirror glass was developed; when combined with double glazing, its insulating value approaches that of masonry, but the esthetic effect seems to be a denial of the form of the building: all it does is reflect what’s around it.

Given that the two significant advantages of curtain wall construction are the reduction of weight and speed of erection, it might be concluded that it costs less than conventional work. That is not necessarily true, because its behavior as an environmental filter, especially in relation to heat flow, may result in higher air-conditioning costs. Often, the preciousness of the architect’s detailing increases costs, as evidenced by Mies van der Rohe’s bronze-and-brown-glass Seagram Building (1954–1958) in New York City. It cost $36 million, approximately twice as much as office towers normally did.

The tall glass prism was the major contribution of the United States to the so-called International Style of modern architecture. But its glorious day passed with the rise of postmodernism, and the crystal towers that Frank Lloyd Wright dismissed as “glass boxes on stilts” were replaced with less anonymous designs. Even Philip Johnson, Mies van der Rohe’s most ardent disciple, forsook the minimalist forms of curtain-wall architecture in favor of a more congenial architecture.

Crystal Palace | London, England

2007-06-23T20:40:00.000-07:00

Crystal Palace

London, England

The Crystal Palace, a vast demountable building designed by Joseph Paxton for the Great Exhibition of 1851 in Hyde Park, London, was in many ways crucial in the development of architecture: it was the pinnacle of innovative metal structure, it revealed the exciting potential of efficient prefabrication, and it was an early demonstration of the modern doctrine that beauty can exist in the clear expression of materials and function. Altogether, it was one of the most noteworthy buildings of the nineteenth century.

The idea for a Great Exhibition came from the Society for the Encouragement of Arts, Manufactures, and Commerce, and was given impetus by Henry Cole, then an assistant keeper in the Public Records Office. His wide interests extended to the publication of The Journal of Design that encouraged artists to design for industrialized mass production and urged manufacturers to employ them. That, he believed, would raise the quality of everyday articles. Cole was elected to the society’s council in 1846, and the following year, with others, he successfully solicited Queen Victoria’s consort, Prince Albert of Saxe-Coburg-Gotha, to accept the role of its president. Under Royal Charter, and spurred by the success of French industrial expositions since 1844, the society held Exhibitions of Art Manufactures from 1847 through 1849.

After visiting the exclusively French exhibition in Paris in 1849, Cole realized that an international show would inform British industry of progress (and commercial competition) elsewhere in the world. Prince Albert, convinced that “that great end to which all history points—the realization of the unity of mankind” was imminent, caught the vision. The Royal Commission for the Exhibition of 1851 was established to expedite a self-financing “large [exhibition] embracing foreign productions.” It was envisioned as “a new starting-point from which all nations will be able to direct their further exertions,” but it was at the same time an expression of British nationalism. Britain had led the world into the Industrial Revolution, and her outlook was smug, to say the least. The Great Exhibition would provide a vehicle to flaunt her industrial, military, and economic superiority and justify her colonialism.

The show was to have a display area of 700,000 square feet (66,000 square meters), much bigger than anything the French had managed. That was too large even for the intended venue in the courtyard of Somerset House, so it was decided to locate it in Hyde Park. An open competition for the design of a building for the “Great Exhibition of the Works of All Nations” attracted 245 entries from 233 architects, including 38 from abroad. The Commissioners’ Building Committee liked none of them; besides, it was unlikely that any could have been completed on

time. Having prepared its own plan for a large dome standing on a brick drum, the committee called for bids. The result was alarming: building materials alone would have devoured at least half of the available funds of £230,000. Anyway, the design was generally considered ugly, especially by the architects whose proposals bad been rejected.

Fox and Henderson and Company, a firm of contractors, engineers, and ironmasters, tendered a price for an alternative, based on a design by the gardener Joseph Paxton. In 1826 Paxton had been appointed head landscape gardener at Chatsworth, the Derbyshire estate of the sixth Duke of Devonshire. He built large conservatories there, including one in 1886–1840 for the giant water lily, Victoria regia. Paxton claimed that his design for the Great Exhibition building was inspired by the structure of that lily, whose cross ribs strengthened the main radial ribs.

Learning that the invited architects had been turned down, Paxton had sketched out his proposal on a sheet of blotting paper—romantic tradition says it was during a train journey—and through a lucky meeting with a mutual friend he was able to show it to Cole. The idea was simple: a modular structure of a single cross section, built from prefabricated metal components, could be repeated ad infinitum to produce a building of any size. Paxton promised Cole that he would have detailed designs ready within a fortnight. In fact, they were completed in nine days and passed to Fox and Henderson on 22 June 1850. By then, the provision of a building was becoming urgent. Paxton’s proposal had the desirable advantage of rapid construction; moreover, unlike the other schemes, it could later be demounted to leave Hyde Park relatively undisturbed. The commission accepted it; the only modification asked for was a vaulted transept so the building could contain without damage the large elm trees on the site.

The Crystal Palace, as it was soon dubbed, was a single space, 1,851 feet long and 456 wide (554 by 136 meters), rising by 20-foot (6-meter) increments across flanking tiered galleries to a 66-foot-high (20-meter) central nave. It was intersected in the middle by a 108-foot-high (32-meter) vaulted transept. The building covered 19 acres (7.6 hectares) of Hyde Park. A filigree of 330 slender, cast-iron columns and arcades supported its clear glass walls and roofs and the wrought-iron beams that carried the galleries, alternately 24 feet (7.2 meters) and 48 feet wide.

Due largely to Paxton’s consummate organizational skills, Fox and Henderson accomplished its construction between September 1850 and January 1851. The Birmingham glassmaking firm of Chance Brothers supplied almost 294,000 panes, which were fixed in a specially designed roof-glazing system based on economical 49-inch-wide (1.25-meter) sheets that determined the module for the entire design. Building work oil-site consisted mostly of assembling the 3,920 tons (3,556 tonnes) of cast-iron components that came from ninety different foundries throughout Britain, often cast less than a day before they were fixed. The accuracy obtained through prefabrication and the mechanical fixing dramatically reduced the proportion of nonproductive labor common to traditional construction methods. Cast-iron columns were strength-tested, and on-site milling and machine painting included miles of timber-glazing bars. The building was decorated in red, green, and blue, and the columns were brightened with yellow stripes. The Crystal Palace established internationally a style and a standard for exhibition pavilions, next at Cork (1852), then at Dublin and New York (both in 1853), and Munich (1854).

The Great Exhibition opened on 1 May 1851, with more than 13,000 exhibits from around the world. By the time it closed six months later, over 6.2 million people had visited it. Despite popular insistence that the building should remain, it was scheduled for dismantling. A consortium bought it and it was, under Paxton’s supervision, reerected in a modified form in a park designed by him at Sydenham Hill, southeast London. Reopened by Queen Victoria in June 1854, the Crystal Palace became a national center for exhibits of industry, art, architecture, and natural history, all held under the auspices of the Crystal Palace Company. Sporting events took place in the park from about 1857 and for twenty years after 1895 it became the venue for Football Association Cup finals. Motor racing followed in 1936.

In November of that year, the Crystal Palace was destroyed by fire. Only one terrace of the original park now survives, and even that is under threat. The Crystal Palace Partnership, with representatives of five London boroughs and private-sector groups, is undertaking a £150 million regeneration scheme for Crystal Palace Park that includes its “restoration,” a concert platform, modernization of the National Sports Centre, and a so-called new Crystal Palace on the surviving 12-acre (4.8-hectare) terrace. The latter, an insensitive proposal for a utilitarian building housing a twenty-screen cinema multiplex with restaurants, bars, and rooftop parking for a thousand cars, provoked local residents to launch the Crystal Palace Campaign in May 1997. A challenge to the scheme is being mounted in the High Court on the grounds that the Crystal Palace Act of 1990 provides that any building on the site should be “in the style and spirit of the former Crystal Palace.”

Confederation Bridge, Prince Edward Island Canada

2007-06-23T20:39:00.000-07:00

Confederation Bridge, Prince Edward Island

Canada

The 8-mile-long (12.9-kilometer) Confederation Bridge, which crosses the Northumberland Strait between Jourimain Island, New Brunswick, and Borden-Carleton on Prince Edward Island, is the longest bridge over ice-covered water in the world. Its daring conception, the quality of its engineering, and the logistics of its realization are among the factors that make it one of the great constructional feats of the twentieth century. The project is also environmentally, politically, and culturally significant.

Prince Edward Island, on Canada’s Atlantic coast, is the nation’s smallest province, with a population of around 130,000. It lies in the Gulf of St. Lawrence at an average of 15 miles (24 kilometers) across the strait from mainland New Brunswick and Nova Scotia. The strait freezes for up to three months every year, and links with the island historically were expensive, freight and passengers having to be moved by ferry. In 1912 the Canadian government decided to build a railcar ferry to run between Borden-Carleton and Cape Tormentine, New Brunswick, and the Prince Edward Irland was commissioned in 1917. In the first year she made only 506 round-trips. In 1938, as a response to wider automobile ownership, a car deck was added, and the vessel continued to operate until 1969. The subsequent decades saw improvements to the service, and new ferries now make the seventy-five-minute crossing at hour-and-a-half intervals. Prince Edward Island has become a vacation resort and by the beginning of the 1990s tourism had joined commercial fishing and agriculture as a mainstay of its economy.

Between 1982 and 1986 several consortia approached Public Works Canada (PWC) with proposals for a privately financed permanent link between the island and the mainland. Three were for bridges (the first estimated at Can$640 million), one for a tunnel, and another for a combined causeway-tunnel-bridge link. In December 1986, the central government instructed PWC to commission feasibility studies of fixed-link alternatives. By June 1987 twelve expressions of interest were in hand, and the acceptance of Strait Crossing’s proposal was announced in

December 1992. Strait Crossing Development (SCD), a consortium of Janin Atlas, Ballast Nedam Canada, and Strait Crossing, was established to develop, finance, build, and operate the Confederation Bridge.

The proposal, put before the island population in a plebiscite the following January, was generally supported, but lobster fishermen and conservationists raised concerns that led to protracted delays. Their conservation measures won for the contractors the Canadian Construction Association’s 1994 Environmental Achievement Award. Working with the Canadian Wildlife Service, SCD provided nesting platforms for endangered osprey in Cape Jourimain National Wildlife Area. The consortium also initiated a Lobster Habitat Enhancement Program, using dredged material to establish new lobster grounds in three formerly nonproductive locations. Construction work commenced in mid-July 1995.

The shore-to-shore Confederation Bridge consists of three parts. The 1,980-foot (0.6-kilometer) east approach from Borden-Carleton and the 4,290-foot (1.3-kilometer) west approach from Jourimain Island, New Brunswick, join the 6.9-mile (11-kilometer) main bridge across the narrowest part of the Northumberland Strait. Its two-lane carriageway rises from 120 feet (40 meters) to 180 feet (60 meters) above the water at the central navigation span. The bridge takes about ten minutes to cross at the design speed of 50 mph (80 kph).

Engineers designed for a 100-year life, taking into account the combined severe effects of wind, waves, and ice. In part, this was achieved by using concrete up to 60 percent stronger than normal in construction. The concrete employed in the 60-foot-diameter (20-meter) ice shields, designed to break up the ice flow at the pier bases, was more than twice normal strength. Because climatic conditions limited on-site construction to six months of the year, the bridge was designed to be assembled in the summers from posttensioned concrete components precast during the winters. The parts of the approach bridges were cast at a staging facility in Bayfield, New Brunswick, transported by land or water to the site, and assembled by a twin launching truss with a traveling gantry crane. Another staging facility was set up in Borden-Carleton to precast the 175 main bridge components. Some weigh as much as 8,000 tons (8,128 tonnes); the main box girders are 570 feet (190 meters) long, yet designed to be joined with tolerances of less than 1 inch (2.54 centimeters).

In August 1995 a purpose-built floating crane, the Svanen, began placing the components of the east approach bridge, completing it in November; the west approach was built the following spring. The main bridge followed, and by August 1996 the navigation span was the last to be placed. On 19 November the structure was complete: sixty-five reinforced concrete piers, founded on bedrock, supported the 8-mile (12.9-kilometer) superstructure which curves gracefully across Northumberland Strait. During the next six months, the finishing work—the polymer-modified asphalt cement road surface, traffic signals, emergency call boxes, weather monitoring equipment, closed-circuit television cameras, and toll booths—was carried out, and the bridge was opened on 31 May 1997. The estimated direct construction cost was Can$730 million.

Colosseum (Flavian Amphitheater) Rome

2007-06-23T20:38:00.000-07:00

Colosseum (Flavian Amphitheater)

Rome

The Flavian Amphitheater, now in ruins, towers over the southeast end of the Roman Forum, between the Esquiline and Palatine Hills. Its popular name, the Colosseum, was derived from the nearby colossal (120-foot-high, or 37.2-meter) bronze statue of Nero, long since vanished. The most ambitious example of a new building type associated with urbanization, the Colosseum was an architectural feat, even by Roman standards. Its size is awesome, but the logistics of moving crowds to and from their seats was also a major achievement.

The earliest amphitheater on the site was built in timber for the pontifex maximus Gaius Scribonius

Curio in 59 b.c.; that; was replaced about thirty years later by a stone-and-timber version for Augustus Octavian Caesar, the first emperor. The Colosseum was commissioned in a.d. 69 by Vespasian, whose son Titus dedicated it in a.d. 80. The highest part of that structure was also timber, and not rebuilt in stone until after a.d. 223. It seems that the first three ranges of seats were completed in Vespasian’s reign, that Titus added two more ranges, and that Domitian completed the building around 300. Although early sources claim that the Colosseum seated 87,000 spectators, modern scholarship puts the figure closer to 50,000. Other Italian amphitheaters at Capua, Verona, and Tarragona are of similar size. The vast Colosseum, elliptical in plan, measured 620 by 510 feet (189 by 156 meters), covering nearly 6 acres (about 2.4 hectares). Its general height was 160 feet (49 meters).

The structural skeleton of the Colosseum was made of travertine limestone, quarried at Tivoli in the hills near Rome and transported to the site along a specially built road. Travertine blocks, some of them 5 feet high and 10 feet long (1.5 by 3 meters), were fixed together with metal cramps to form concentric elliptical walls. These were linked with radiating tufa walls carrying complex rising vaults of brick-faced concrete, in which volcanic stone such as pumice was used to reduce the weight. The vaults carried the tiers of seats. The Colosseum was built to house extravagant spectacles that took place in an arena measuring 280 by 175 feet (86 by 54 meters). Apart from a number of minor entrances to the arena, there were four principal gates at the ends of the axes, directly joined by passages to the exterior. A 15-foot-high (4.5-meter) walls probably faced with marble, defined the arena and provided a measure of protection for the spectators. The floor of the arena was made of heavy planks, strewn with sand for the purpose of soaking up the blood of gladiators, prisoners of war, and wild animals that died in their thousands. Such emperors as Caligula and Nero even ordered cinnabar and borax to replace the sand. A labyrinth of chambers beneath the floor possibly housed the participants in the games, and there were complicated machines and hoists to lift men, beasts, and theatrical sets into the arena, adding to the spectacle. Sometimes the entire floor was removed and the arena flooded by a system of pipes so that galleys could be pitted against each other in mock naval battles.

The terrace on top of the surrounding wall was wide enough to contain two or three rows of movable seats. Undoubtedly the best in the house, they were reserved for senators, magistrates, the vestal virgins, and other important people. The emperor and his immediate retinue occupied an elevated cubiculum. Upon entering the Colosseum through numbered arches corresponding to their ticket numbers, other visitors climbed sloping ramps to the gradus (bleachers), which were divided into stories and allocated according to gender and social class. The first fourteen rows of marble seats were covered with cushions and set aside for the equestrian order. Above them a horizontal space defined the second range, where a third class of spectators, the populus, was seated. Still further up were the wooden benches for the common people. The open gallery at the very top was the only part of the amphitheaters from which women were permitted to watch. There were exceptions, of course. When the games were over, the crowd could quickly disperse through no fewer than sixty-four strategically placed exits, aptly known as vomitoria.

The external wall of the Colosseum was divided into four stories, reflecting the circulation corridors within. Its eighty arches, most of which provided access to the interior, were framed by superimposed orders of pilasters (nonstructural columns): Tuscan on the ground floor, Ionic above them, and Corinthian at the top. The fourth story, also embellished with Corinthian pilasters, had stone brackets for the wooden masts from which an awning (velarium) was suspended across the interior to shield spectators from the sun while they watched the slaughter below. Many of the visible parts of the building were enriched with moldings, ornament, facings of marble or polished stone, and statuary. Fountains of scented water were provided for refreshment.

The Flavian Amphitheater was damaged several times by lightning strikes and repaired as often, so that games continued spasmodically until the sixth century, despite the opposition of the church and some Christian emperors. The last recorded slaughter of wild beasts was in the reign of Theodoric (a.d. 454–526), since when it has been used sometimes as a fortress and (to its detriment) as a quarry. Renaissance palaces in Rome, such as the Cancellaria and the Farnese, and churches including Saint Peter’s Basilica, were built with columns plundered from the ancient monument. Various popes made efforts to preserve it, and in 1750 Pope Benedict XIV consecrated it to the martyrs who died there. Surprisingly, and despite popular belief, it was not the main venue for the execution of Christians. In 1996 a U.S.$25 million restoration of the Colosseum was launched. After the cellars were drained, fallen masonry replaced, bushes and weeds cleared from the arena, and the structure repaired and cleaned, the greatest amphitheater was reopened in July 2000 with a season of Greek plays.

CN (Canadian National) Tower | Toronto, Canada

2007-06-23T20:37:00.000-07:00

CN (Canadian National) Tower

Toronto, Canada

The CN Tower, next to the city hall on Front Street, Toronto, stands on the shore of Lake Ontario. It transmits television and FM radio for more than twenty broadcasters, as well as serving various other communications purposes. Including the masts, it is the tallest freestanding structure in the world; the top of the transmission antenna is over 1,815 feet (553 meters) high. But at the beginning of the twenty-first century, as technically demanding as it is, height alone does not constitute an architectural feat. The twin Petronas Towers in Kuala Lumpur, Malaysia, currently rank as the world’s tallest buildings, at 1,483 feet (454 meters). Others are proposed that will exceed that, including the 1,660-foot (508-meter) Taipei Financial Center on Taiwan, to be completed in August 2002, and the 2,100-foot (642-meter) Russia Tower in Moscow; at 2,755 feet (843 meters), the Millennium Tower in Tokyo will dwarf them all. The CN Tower is remarkable architecture because of its construction technique. For about a year, concrete, mixed and tested on-site to ensure consistent quality, was poured around the clock into a “slip form” that gradually decreased in diameter, to create the elegantly tapered contour of the post tensioned hollow structure.

Slip forming is a rapid construction technique based on extrusion. It employs a self-raising formwork that continually moves upward as the concrete is being placed, at a rate that gives the concrete time to set before being exposed as the formwork rises on a ring of hydraulic jacks, developing enough strength to support the work above. Continuous slip forming obviously speeds up the construction process while enabling excellent quality control, optimizing labor, and reducing the cost of building plant and scaffolding. It also results in monolithic, seamless structures. Developed in North America in the 1920s—The Granary at Logan Square in Philadelphia (1925) was one of the first examples in the United States—it has been widely used to build grain silos, building service cores, and (normally) any tall structures with a consistent cross section.

Early in the 1970s the number of multistory office blocks in downtown Toronto increased significantly, with a consequent interference with television and radio reception in large parts of the city. Toronto needed an antenna taller than any existing office block, indeed, of any that was anticipated, and the CN Tower was proposed to meet that need. The project was initiated in 1972 by the Canadian National Railway, which commissioned John Andrews Architects, working in collaboration with Webb Zerafa Menkes Housden Architects of Toronto. The structural engineering consultant was Roger R. Nicolet of Montreal; the mechanical and electrical engineers were Ellard-Wilson Associates Ltd. of Toronto; and the manager-contractor was Foundation Building Construction.

The original design proposed three concrete towers linked by structural bridges, but that was developed into a single tower with three hollow “legs.” As well as serving as electrical and mechanical service ducts, the hollow columns provided the necessary degree of flexibility for such a tall structure. Construction started in February 1973, and in four months a Y-shaped, 22-foot-thick (6.7-meter) reinforced concrete base was founded on the bedrock 50 feet (15 meters) beneath the city. The continuous slip-form process then began. When the tower reached 1,100 feet (336 meters), a seven-story “SkyPod,” fabricated on the ground, was raised into position

and anchored by twelve steel-and-timber brackets that were slowly pushed up the tower by forty-five hydraulic jacks. The concrete-walled SkyPod, reached by four high-speed, glass-fronted elevators, houses a 400-seat revolving restaurant, a nightclub, and indoor and outdoor observation decks. Later, a 2.5-inch-thick (6.4-centimeter) glass floor was installed. Beneath the SkyPod, delicate microwave dishes and other broadcasting equipment are protected by an annular radome. The concrete tower continues to the Space Deck at 1,465 feet (447 meters)—an observation gallery that on a clear day provides a view with 100-mile (160-kilometer) visibility. A Sikorsky Skycrane helicopter lifted the tower’s 335-foot (100-meter) communications mast in forty sections, each of about 7 tons (6.4 tonnes), and they were bolted together in place. The mast, erected in three weeks, was covered by fiberglass-reinforced sheathing. The maximum sway experienced at the very top in 120-mph (190-kph) winds with 200-mph (320-kph) gusts is 3.5 feet (1.07 meters).

CN (Canadian National) Tower, Toronto, Canada. John Andrews and Webb Zerafa Menkes Housden Architects; Roger R. Nicolet, structural engineer, 1972–1975. View from Lake Ontario.

The CN Tower was completed in June 1975 and officially opened on 1 October. It cost Can$57 million and took about 1,550 workers forty months to construct. It is nearly twice the height of the Eiffel Tower and more than three times as tall as the Washington Monument. Soaring above Toronto, it is struck by lightning about seventy-five times every year.

In 1995 Canada National passed ownership to a public company, the Canada Lands Company. In June 1998, the CN Tower officially opened a 75,000-square-foot (7,100-square-meter) expansion including an entertainment center, shopping facilities, and restaurants.