http://en.wikipedia.org/wiki/Salar_de_Uyuni
Salar de Uyuni (or Salar de Tunupa) is the world's largest salt flat at 10,582 square kilometers (4,086 sq mi). It is located in the Potosà andOruro departments in southwest Bolivia, near the crest of the Andes, and is elevated 3,656 meters (11,995 ft) above mean sea level.[1] The Salar was formed as a result of transformations between several prehistoric lakes.
Salar is salt flat in Spanish and Uyuni originates from the Aymara language and means a pen (enclosure). Thus Salar de Uyuni can be loosely translated as a salt flat with enclosures, the latter possibly referring to the "islands" of the Salar. Uyuni is also the name for a town of 10,600 people, which serves as a gateway for tourists visiting the Salar.
The crust serves as a source of salt and covers a pool of brine, which is exceptionally rich in lithium.
Underneath the surface of the Salar is a lake of brine 2 to 20 meters (7 to 66 ft) deep. The brine is a saturated solution of sodium chloride, lithium chloride and magnesium chloride in water. It is covered with a solid salt crust with a thickness varying between tens of centimeters to a few meters. The center of the Salar contains a few "islands", which are the remains of the tops of ancient volcanoes which were submerged during the era of lake Minchin. They include unusual and fragile coral-like structures and deposits that often consist of fossils and algae
