The Salar de Uyuni, located in Bolivia, is the largest salt flat in the world. Measuring in at over 4,000 square miles, the Salar was once part of a prehistoric salt lake that covered much of Southwestern Bolivia. The lake dried up, leaving a massive layer of salt crust almost 12,000 feet above sea level.
Salar de Uyuni attracts tourists from around the world. As it is located far from the cities, a number of hotels have been built in the area. Due to lack of conventional construction materials, many of them are almost entirely (walls, roof, furniture) built with salt blocks cut from the Salar. The first such hotel was erected in 1993–1995 in the middle of the salt flat, and soon became a popular tourist destination
The Salar contains a large amount of sodium, potassium, lithium, and magnesium (all in the chloride forms of NaCl, KCl, LiCl, and MgCl2, respectively), as well as borax.
Of those, lithium is arguably most important as it is a vital component of many electric batteries. With estimated 9,000,000 tonnes (8,900,000 long tons; 9,900,000 short tons), Bolivia holds about 43% of the world’s known lithium reserves; most of those are located in the Salar de Uyuni.