It is the largest salt flat (= span. salar) in Chile, containing the world´s largest and purest active source of Lithium. Chile exports about 30% of the annual world´s lithium supply, followed by China. As tourist you don´t get to see those industrial mining plants but nature reserves like laguna Cejar.
To get there you have to leave the tarmaced and get on to the gravel road, sometimes up to 25 km. So it is worthwhile to have a 4WD car.
In laguna Tebinquiche it is permitted to swim, one can float like in the Dead Sea.