Salar de Uyuni (or: Salar de Tunupa) is with its 10,582 km². (4,085 square miles) [1] the world's largest salt flat. It is located in the west Departmento of Potosí and of south of Oruro in southwest Bolivia, near the crest of the Andes, 3650 meters high. The major minerals found in the salar are halite and gypsum.

Some 40,000 years ago, the area was part of Lake Minchin, a giant prehistoric lake. When the lake dried, it left behind two modern lakes, Poopó and Uru Uru, and two major salt deserts, Salar de Coipasa and the larger Uyuni. Uyuni is roughly 25 times the size of the better-known Bonneville Salt Flats in the United States.

Salar de Uyuni is estimated to contain 10 billion tons of salt of which less than 25,000 tons is extracted annually. All miners working in the Salar belong to Colchani's cooperative. They work from dawn to dusk and most of them do not take a lunch break in order to take advantage of time, getting energy by chewing coca leaves. Every November, Salar de Uyuni is also the breeding grounds for three species of South American flamingos - Chilean, James's and Andean. It is also a significant tourist destination; highlights include a salt hotel and several so-called islands.

Uyuni is a town in the Potosí Department in the south of Bolivia. Founded in 1890 as a trading post, the town has a population of 10,600 (2006 official estimate). The town has an extensive street-market. It lies at the edge of an extensive plain at an elevation of 3670 meters above sea level, with more mountainous country to the east. There is little agriculture in the area, because water supplies are scarce and somewhat saline. Today the town's primary function is as a gateway for tourists visiting the world's largest salt flats - the Salar de Uyuni.