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.