Back-breaking work. A woman work's her family's salt pool in Maras, Peru. She is squeezing the moisture out of the salt before letting it sit out in the sun to dry. This salt mine has been worked since Inca times owned cooperatively among the families of Maras. The salt comes from a subterranean stream. The water comes out at a spring by the mines. The flow is channeled into many tiny canals that direct the water gradually downslope to the numerous terraced pools. Almost all the pools are less than four meters square in area, and none exceeds thirty centimeters in depth. They are shaped into polygons with the flow of water carefully controlled and monitored by the workers. The altitude of the pools slowly decreases, so that the water may flow through the myriad branches of the water-supply channels and be introduced slowly through a notch in one sidewall of each pond.