Salar de Uyuni is the world’s largest salt flat at 10,582 square kilometers. It is located in the Potosi and Oruro departments in southwest Bolivia, near the crest of the Andes. The Salar 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 altitude variations within one meter over the entire area of the Salar. The large area, clear skies and the exceptional flatness of the surface make the Salar an ideal object for calibrating the altimeters of Earth observation satellites. The Salar serves as the major transport route across the Bolivian Altiplano and is a major breeding ground for several species of pink flamingos. Salar de Uyuni is also a climatological transitional zone, for towering tropical cumulus congestus and cumulus incus clouds that form in the eastern part of the salt flat during the summer cannot permeate beyond its drier western edges, near the Chilean border and the Atacama Desert.