Once an ancient lake the 'Salar de Uyuni' was formed as a result of transformations between several prehistoric lakes. It is covered by a few meters of salt crust, which has an extraordinary flatness with the average elevation variations within one meter over the entire area of the Salar. The crust serves as a source of salt and covers a pool of brine, which is exceptionally rich in lithium. It contains 50% to 70% of the world's known lithium reserves,which is in the process of being extracted. The large area, clear skies, and exceptional flatness of the surface make the Salar an ideal object for calibrating the altimeters of Earth observation satellites. (Wikipedia)
Incahuasi has a total area of 24.62 hectares (61 acres) and hosts gigantic cacti (Trichocereus pasacana). There are unusual and fragile coral-like structures and deposits that often consist of fossils and algae. The place is the top of the remains of an ancient volcano, which was submerged when the area was part of a giant prehistoric lake, roughly 40,000 years ago.