Salar de Uyuni: The World’s Giant Mirror Salt Flat

Salt flat in Bolivia

Salar de Uyuni is the largest salt flat in the world, with an area of approximately 10,582 square kilometres (4,086 mi). It is situated in southwestern Bolivia, within the Daniel Campos Province of the Potosí Department, near the crest of the Andes Mountains, at an elevation of 3,656 m (11,995 ft) above sea level.

The Salar was formed as a result of transformations of seven Late Pleistocene lakes whose progressive desiccation led to the accumulation of extensive evaporitic salt deposits. It is now covered by an 8-meter-thick layer of salt, which is extremely flat. The average elevation varies by less than 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. The large area, clear skies, and exceptional flatness of the surface make the Salar ideal for calibrating the altimeters of Earth observation satellites. Following rain, a thin layer of dead calm water transforms the flat into the world’s largest mirror, 129 km (80 miles) across.

The Salar serves as the major transport route across the Bolivian Altiplano and is a prime breeding ground for several species of flamingos. Salar de Uyuni is also a climatological transitional zone since the towering tropical cumulus congestus and cumulonimbus 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.

The Salar has been used as a filming location for movies such as The Fall (2006), Salt and Fire (2016), The Unseen (2017), Star Wars: The Last Jedi (2017), and several others.