Building a 25,000 Mile Road with only Stone, Wood and Bronze Tools

This 500 year old Incan road is an engineering feat that is still in use.

Qhapag Ñan (the Road of the Lord), runs across the South-American coastline from Ecuador to Chile, the entire system covers 40,000 km (25,000 mi).

Qhapag Ñan (the Road of the Lord), runs across the South-American coastline from Ecuador to Chile, the entire system covers 40,000 km (25,000 mi).

Imagine a system of roads stretching through the South-American coastline, from Ecuador to Chile, running about 40,000 km (25,000 mi) through mountains, plains and deserts. This is Qhapag Ñan (the Road of the Lord), or what is commonly known as the great Inca road. Constructed more than 500 years ago, with some of its paths predating the Incan Empire itself, the road is still in use. It is now considered one of the world’s greatest engineering feats.

How was it that these Incan engineers, without the use of metal, the wheel, or even stock animals were able to build such a wonder?

While some parts of the road are little more than paths carved in the dirt, the Inca road includes bridges, causeways, stairways and stations for travellers to stop and rest. The roads were built using only wooden, stone and bronze tools according to an article published on Ancient History Encyclopedia, by Mark Cartwright.

Non-uniform in design, the roads were built by local populations with often varying designs and materials. Wider paths stretch to 15 meters, like the highway in the Huánuco Pampa province. Flattened road beds were often packed with soil, sand or grass. Key roads were ornately outlined with stones.

Doug McMains / National Museum of the American Indian. © 2015 Smithsonian Institution.

Doug McMains / National Museum of the American Indian. © 2015 Smithsonian Institution.

Rainwater was diverted from the road’s surface by culvert-like designs, with causeways to travel over wetlands. Stone bridges were built to cross rivers.  Roads between desert oases were marked by low walls or cairns, writes K. Kris Hirst.

The great Inca road is primarily built along straight lines, with no more than 20 degrees of deflection within a 5km (3 mi) stretch, Hirst adds. The road’s longest straight-line stretch measures 3,200 km (2,000 mi). This long stretch of road was likely used for communicating and trading with neighbouring villages and empires, or moving military forces and ensuring political control against the same. Today, the road is venerated as a cultural symbol worth preserving not only as a feat of engineering, but as a reminder of a culture that survived the Spanish invasions.

In celebration of the Inca road, the Smithsonian’s National Museum of the American Indian will present an exhibit titled “The Great Inka Road: Engineering an Empire,” June 26, 2015 through June 1, 2018. The exhibit will detail the history of the Incan Empire in 11 sections and will explore how the road was constructed, the engineering solutions used in its design, how the road was used and more.

To learn more about Qhapag Ñan, the great Inka road and its Smithsonian exhibit, visit www.nmai.si.edu.