Salar de Uyuni 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. When it is covered with water, the Salar de Uyuni reflects the sky.

Url: http://fogonazos.blogspot.com/2008/03/most-amazing-natural-mirror-in-world.html