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.
Some 40,000 years ago, the area was part of Lake Minchin, a giant prehistoric lake. When the lake dried, it left behind two modern lakes, Poopó Lake and Uru Uru Lake, and two major salt deserts, Salar de Coipasa and the larger Uyuni. Uyuni is roughly 25 times the size of the Bonneville Salt Flats in the United States.
Salar de Uyuni is estimated to contain 10 billion tons of salt, of which less than 25,000 tons is extracted annually. All miners working in the Salar belong to Colchani's cooperative. Every November, Salar de Uyuni is also the breeding grounds for three species of South American flamingos: the Chilean, James's and Andean flamingos. It is also a significant tourist destination; highlights include a salt hotel and several so-called islands. As it is so flat it serves as a major transport route across the Bolivian Altiplano.
Also, Salar de Uyuni holds half of the world's reserves of lithium, a metal which is used in high energy density lithium batteries. There is currently no mining plant at the site and the Bolivian government doesn't want to allow exploitation by foreign corporations, but instead it intends to build its own pilot plant.
Due to its large size, smooth surface, high surface reflectivity when covered with shallow water, and minimal elevation deviation, Salar de Uyuni makes an ideal target for the testing and calibration of remote sensing instruments on orbiting satellites used to study the Earth. In addition to providing an excellent target surface the skies above Salar de Uyuni are so clear, and the air so dry, that the surface works up to five times better for satellite calibration than using the surface of the ocean. In September 2002 a team took detailed GPS elevation measurements of a portion of the salt flats. This GPS data was then compared to the data from several ICESat passes over the area were used to evaluate the accuracy and precision of ICESat's instruments.
Traveler's Tips
1. Four day tours cost around $80 including food and lodging. This does not include the park entrance fee or your guide’s tip.
2. It is cheapest to book a tour in Uyuni—the train station is bustling with tour hawkers, although in high tourist season (June-August) business get busy.
3. Hotels (and simple restaurants) abound in Uyuni, most boast tourist lures like hot showers, but are otherwise basic.
4. There are dozens of tour agencies in Uyuni. Your guidebook will list some options. Colque Tours () appeared to be the biggest and most polished of the lot; personally, we were turned off by their long (albeit shiny and new) caravan. We booked weeks ahead with Tonito Tours but we were passed off by Tonito to Tunupa Tours and, although inconvenienced, we were not disappointed. (Search for the latest dirt on agencies!)
5. Bring cash (Bs. or $US)in low denominations and good condition (dirty money will be rejected). There are banks in Uyuni but lines are long and frustrating. There are exchange offices, but they run out of money.
6. WARNING: do not attempt to buy your train tickets to Uyuni in Oruro, the town where you catch the train. In travel agencies in La Paz, you can buy tickets ahead, but in Oruro you must buy the day of your trip; the line starts to form around midnight the night before. In a pinch, a pre-dawn arrival will cost you half a day waiting, but will get you a seat.
7. Acclimate to the altitude in Bolivia before setting off into remote areas like Uyuni and beyond.
8. What to bring: PLENTY of water, serious sun protection (including hat, sunscreen, and, most crucially: sunglasses), warm clothing, and lots of film (bring low speeds for bright light!).
