Salar de Uyuni is in Bolivia, so Bolivia is the answer to the question about the country containing the world’s largest salt flat. It occupies part of Bolivia’s high Altiplano in the country’s southwest.
Covering approximately 10,582 square kilometres, Salar de Uyuni is an enormous, exceptionally flat salt crust at about 3,656 metres above sea level. It formed as several Late Pleistocene lakes gradually dried, leaving thick evaporite deposits. Beneath the crust lies brine rich in sodium chloride, magnesium chloride and lithium.
During the rainy season, a thin layer of water can cover the surface and produce the famous mirror effect. The flat’s vast size, bright surface and minimal elevation variation also make it valuable for calibrating Earth-observation satellites. Islands such as Incahuasi rise from the salt as remnants of ancient volcanic landforms.
It is sometimes confused with smaller salt flats in Argentina, Chile or the United States. Bolivia’s Salar de Uyuni is the largest salt flat, not simply the most photographed one.