The Inca Empire was an ancient civilization in South America. They lived in the mountains of Peru and parts of Bolivia, Ecuador and Chile. They were very powerful and their people were skilled in farming, weaving, and metalworking. They built a big network of roads that connected all the different parts of their empire. They also had a huge trading network, so they could trade goods with other cultures in the area. The Incas used a kind of writing called "Quipu" and had a number system based on 10s. Their leader was called the Sapa Inca. He was very powerful and ran the government. The Inca Empire lasted from about 1400 AD to 1536 AD, when the Spanish invaded.