The Incas lived in the Andes mountains of South America and were ruled by an emperor called the Inca. They were skilled builders who constructed huge cities out of massive stone blocks that fit together perfectly. These cities contained temples, palaces, and observatories and the most famous is Machu Picchu, located high in the Andes mountains. The Incas also built an extensive road network to connect their cities and used runners and llamas to carry messages and goods between them.