For centuries, the vanished Inca fortress of Ancocagua existed only in lore. Now, at a mountaintop site in Peru, researchers are zeroing in on a discovery that could reshape what we know of the empire ...

The Inca Empire in South America, one of the most powerful pre-Columbian societies, was known for many innovations — such as the architecture of Machu Picchu, an extensive road network, and a system ...

Inca bureaucrats recorded all the goings-on in their bustling empire using knotted cords called khipu, where the position and order of the knots represented numbers. They relied on the khipu system to ...