West of the village of Maras are these unusual Inca ruins. Their depth, design and orientation creates a temperature difference of as much as 15°C (27°F) between the top and the bottom. The purpose is uncertain, but it may have been used for agricultural experiments. It has been discovered that the soil of the terraces comes from different places. The Inca have produced countless varieties of potatoes, quinoa and corn. Until 50 years ago, potatoes and barley were grown here.