Salar de Uyuni the biggest worldwide .  It represents a dried-up salt lake, which is located in the south plains of the Altiplano .  The inner part is covered with a thick Uyuni salt, a thickness of 2 to 8 m .  When Bolivia's rainy season begins, the entire surface is covered with a layer of saline water and looks like a huge mirror .  Plane saline unique flat, under several meters of salt crust is a lake depth from 2 to 20 meters .  Salt water which, according to experts comprises 50 to 70% of world reserves of lithium .  Just in the lake a lot of salt and magnesium chloride .  In the heart of the marsh you can see several islands, which in ancient times were the tops of volcanoes .  Their structure is extremely fragile, and is similar to the composition of corals .  That is composed of algae and fossils .  In the area of ​​Salar de Uyuni is usually always a bright sunny weather, the rains here are extremely rare .  Therefore, tourists show a huge flat salt lake on the background of the endless desert plains and blue cloudless sky vegda causes a storm of excitement and a lot of impressions .