Inca Empire

The Inca Empire (1438-1533), the largest empire in pre-Columbian America, administered 12 million people across 2 million square kilometres using a road network of 40,000 km — comparable to Rome's — with no writing system, no wheels, no draft animals, and no currency. Their engineering achievements (Machu Picchu, terraced agriculture, rope bridges spanning gorges), textile traditions, and oral administrative system (quipu) remain extraordinary.