Moray, an Incan archaeological site in Peru on a high plateau at about 3,500 m (11,500 ft). The site contains several unusual enormous terraced circular depressions, the largest of which is about 30 m (98 ft) deep. The purpose of these depressions is uncertain, but their depth and orientation with respect to wind and sun creates a temperature difference of as much as 15 °C (27 °F) between the top and bottom, possibly used by the Inca to study the effects of different climatic conditions on crops. In other words, Moray was perhaps an Inca agricultural experiment station. As with many other Inca sites, it also has a sophisticated irrigation system.