The Inca Empire built 40,000 km of roads — with no wheeled vehicles or horses

At its peak in the 1400s, the Inca Empire stretched 4,000 km along the Andes and connected it with the most extensive road network in the pre-Columbian Americas — roughly 40,000 km of paved roads, tunnels, and suspension bridges. It was used entirely by foot messengers called chasquis, relay runners who could convey messages 240 km per day. There were no wheeled vehicles and no horses until the Spanish arrived in 1532. The Spanish conquistadors, arriving with 168 men and some horses, toppled an empire of 12 million people partly by exploiting internal political fractures.

Source: D'Altroy, T.N., The Incas (Blackwell, 2002)