Salar de Uyuni, Bolivia

Salar de Uyuni (or Salar de Tunupa) is the world's largest salt flat at 10,582 km² (4,085 square miles). It is located in the Potosí and Oruro departments in southwest Bolivia, near the crest of the Andes, 3,650 meters high. The major minerals found in the salar are halite and gypsum.
As it is so flat it serves as a major transport route across the Bolivian Altiplano.

Salar de Uyuni holds half of the world's reserves of lithium, a metal which is used in high energy density batteries (Lithium battery)