A worker carries a bag of salt after collecting it from a pond at the Maras mines in Cuzco December 3, 2014. Salt has been obtained in Maras since pre-Incan times by evaporating highly salty local subterranean stream water. The water is intricately channelled through constructions, flowing gradually down onto several hundred ancient terraced ponds. From each pond, a local member of the mine cooperative can produce 150 to 200 kilos per month which can be sold in the markets at $0.34 per kilogram, according to miners. (Photo by Enrique Castro-Mendivil/Reuters)

A worker washes salt after collecting it from a pond at the Maras mines in Cuzco December 3, 2014. (Photo by Enrique Castro-Mendivil/Reuters)

A view of salt ponds at the Maras mines in Cuzco December 3, 2014. (Photo by Enrique Castro-Mendivil/Reuters)

Workers collect salt from salt ponds at the Maras mines in Cuzco December 3, 2014. (Photo by Enrique Castro-Mendivil/Reuters)

A worker carries washed salt after collecting it from a pond at the Maras mines in Cuzco December 3, 2014. (Photo by Enrique Castro-Mendivil/Reuters)

Workers collect salt from a salt pond at the Maras mines in Cuzco December 3, 2014. (Photo by Enrique Castro-Mendivil/Reuters)

A view of salt collected from a pond at the Maras mines in Cuzco December 3, 2014. (Photo by Enrique Castro-Mendivil/Reuters)

A tourist takes pictures of a salt pond at the Maras mines in Cuzco December 3, 2014. (Photo by Enrique Castro-Mendivil/Reuters)