Salar de Uyuni (or "Salar de Tunupa") is the world's largest salt flat, or playa, at over 10,000 square kilometres (3,900 sq mi) in area. It is in the Daniel Campos Province in Potosí in southwest Bolivia, near the crest of the Andes at an elevation of 3,656 m (11,995 ft) above sea level.. The Salar was formed as a result of transformations between several prehistoric lakes .