The Salar de Uyuni (or "Salar de Tunupa") is the largest salt flat or playa in the world at over 10,000 square kilometers

(3,900 sq mi). It is in the province of Daniil Campos in Potosi in south-west Bolivia, near the crest. of the Andes at an

altitude of 3,656 meters (11,995 ft) above sea level.The Salar was formed as a result of changes between several

prehistoric lakes that existed about forty thousand years ago, but all evaporated over time. It is now covered by a salt crust

of a few meters, which has an exceptional flatness with an average elevation variation. One meter over the entire area of Salar. The crust

serves as a source of salt and covers a pool of brine, which is exceptionally rich in lithium. The large area, clear skies and exceptionala

flatness of the surface make Salar ideal for calibrating the altitude of Earth observationsatellites. After the rain, a thin layer of dead

calm water turns the flat into the world's largest mirror, 129 km (80 mi) across.The Salar serves as the major transport route

in the Bolivian Altiplano and is a major breeding ground for several species of flamingo. The Salar de Uyuni is also a climate transitional

zone because the giant tropical Cumulus congestus and Cumulonimbus Incas clouds that form during the summer in the eastern part

of the salt flat, near the Chilean border and the Atacama Desert, cannot extend beyond its dry western edges.