The Inca civilization was located in the Andes Mountains of South America, with their capital in Cuzco, Peru. They built large stone fortresses and structures without the use of wheels, using rope bridges, terraced farming, and a base-10 counting system to record information. The Sapa Inca, or emperor, ruled over the large empire and had a strict social hierarchy and system of tributes from farmers. European diseases and the Spanish conquistadors led by Francisco Pizarro ultimately conquered the Inca Empire.