The Aztecs conquered the area in the 1470s, and established here a sanctuary for their military elite, the Eagle and Jaguar warriors. The complex was built on the Cerro de los Idolos (Hill of the Idols), over an older ceremonial site. The main attraction of this archeological site is the Cuauhcalli or "House of Eagles". It is one of the few buildings in the world monolithic, i.e. a single stone carving, and only in America.