The salt flat in Bolivia that is the world's largest, covering more than 10,000 square kilometers, is Salar de Uyuni. This immense white expanse occupies part of Bolivia's high Altiplano in the Andes and covers approximately 10,582 square kilometers.
Salar de Uyuni formed when several prehistoric lakes gradually dried up, leaving behind thick evaporite deposits. A solid crust of salt covers brine containing sodium, magnesium, and lithium compounds. The surface is extraordinarily flat, with elevation differences across the salar of less than a meter, making it useful for calibrating Earth-observing satellites.
During the dry season, polygonal salt patterns appear across the crust. After rain, a shallow layer of still water can create a mirror-like reflection of the sky, producing the landscape’s most famous photographs. The salar is also habitat for several flamingo species and contains volcanic islands, including Isla Incahuasi, whose giant cacti rise above the salt. It is often confused with Chile's Atacama Desert, but Atacama is a broader hyper-arid desert region, not the world's largest salt flat.