If it is not, strictly speaking, a real lake, since almost completely dried up, the Salar de Uyuni is the largest salt desert we can observe on Earth, storing 64 billions tons of salt on an area of 10,582 square kilometers. The Salar de Uyuni also holds other associated records: when flooded, it becomes the largest mirror in the world, and it also holds the largest land reserves of lithium.
How did it formed? There are over 30,000 years, in southwest of present-day Bolivia, near the Andes, the huge lake Tauca began to evaporate while giving rise to many smaller bodies of water.
Img : enough to make bretzels for 3 billion years
When these lakes were surrounded by mountains, water then would have only escaped by evaporation, leaving behind the heavy elements and salt residues. The largest of these enclosed water stretches became the great salt lake Salar de Uyuni: as it did not rain enough, water still evaporated but failed to renew. A crust of several tens of cm thick salt formed on thousands of square kilometers that make up the current Salar de Uyuni. This crust covers a large salt sea: a fully salt-saturated solution that no longer looks like the milder antic waters, even more salty, actually, than the famous Dead Sea.
Original source : Le plus grand désert de sel, le Salar de Uyuni. Nature extrême