Salar de Uyuni is the world's largest salt flat. It is located in the Potosà and Oruro departments in southwest Bolivia, near the crest of the Andes, 3,650 meters high. The major minerals in the salar are halite and gypsum. Salar de Uyuni is estimated to contain 10 billion tons of salt, of which less than 25,000 tons is extracted annually.