Salar de Uyuni is the largest salt desert on the earth. It is, for example, twice larger than famous Great Salt Lake in Utah. It has 12 106 square kilometers, salt layer is between 2–20 meters and annually is mined 20,000 tons. In addition, there are interesting black rocks towering from salar like true „islands“. They are covered by several cacti. Dry salt makes interesting geometric polygons here. On the other hand, when is salar after rains full of water, it looks like an endless mirror.