Sacsayhuaman is an Inca site just above the central plaza of Cuzco. Large stone walls exist throughout the complex, some of which extend up to 400 metres in length. There is an estimated 6 cubic kilometres of stone used in the construction of this site. Some of the stones weigh up to 200 tonnes. While the Spanish were successful in removing many of them from the complex in order to construct churches, the largest still remain.