Salar de Uyuni (or Salar de Tunupa) is the world's largest salt flat at 10,582 square kilometers. It is located in the Potosíand Oruro departments in southwest Bolivia, near the crest of the Andes and is at an elevation of 3,656 meters above mean sea level. The Salar was formed as a result of transformations between several prehistoric lakes. It is covered by a few meters of salt crust, which has an extraordinary flatness with the average altitude variations within one meter over the entire area of the Salar.