The Largest Salt Desert in The World – Salar de Uyuni, Bolivia. Salar de Uyuni (or Salar de Tunupa) is the largest salt desert in the world. Salar de Uyuni Altiplano of Bolivia is part of South America. The Altiplano is a plateau that was formed while raising the Andes mountains. Plateau include salt and fresh water lakes and salt flats and is surrounded by mountains. Salar de Uyuni was formed as a result of changes between several prehistoric lakes. It is covered with several feet of salt crust, which is extraordinary flatness with altitude variations within one meter over the entire surface of the Salar. Shell serves as a source of salt and cover a pool of brine, which is exceptionally rich in lithium. It contains 50-70% of world reserves of lithium, which is in the process of being extracted.