Salar de Uyuni

Interesting facts

According to Aymara legend, the flat formed from the tears and milk of Tunupa, a mountain deserted by her giant husband; many locals prefer the name Salar de Tunupa.

The name Uyuni comes from Aymara and means a pen or enclosure.

The flat holds an estimated 10 billion tonnes of salt, of which less than 25,000 tonnes are dug out each year.

At about 10,582 square kilometres, it is roughly 100 times the size of the Bonneville Salt Flats in Utah.

The rocky islands in its centre are the tops of ancient volcanoes once drowned by a prehistoric lake, crusted with fragile coral-like deposits and fossil algae.

Hotels around the flat have walls, roofs and even furniture cut from salt blocks; the first, Palacio de Sal, went up in the middle of the salar in the 1990s.

Near the town of Uyuni lies a cemetery of rusting steam locomotives, abandoned after the region's mining industry collapsed in the 1940s.

The railway those trains ran on was built by British engineers between 1888 and 1892 to haul minerals to Pacific ports.

The salt flat is a major breeding ground for several species of flamingo.

The salt flat was one of the filming locations for Star Wars: The Last Jedi (2017).

Why it is worth it

Salar de Uyuni is not a desert that happens to be white — it is the exposed, dried-out bottom of a chain of prehistoric lakes (geologists call the last big one Lake Tauca) that repeatedly filled and evaporated over tens of thousands of years. Each cycle left another sheet of salt, and today those layers stack up to 10 meters thick over an area the size of a small country. Walking on it, you are walking on the floor of an Ice Age sea.

What you cannot see is more consequential than what you can. Under that white crust sits a brine reservoir holding an estimated 50–70% of the world's known lithium reserves — the metal in almost every phone and EV battery on Earth. That single fact turns Uyuni into a genuine flashpoint: the same flatness and mineral chemistry that make it visually extraordinary also make it one of the most contested resources on the continent, with Bolivia, foreign mining consortia, and local communities all negotiating how much of that brine gets pumped out.

The mirror effect is simpler chemistry than people assume, but the geometry behind it is remarkable. During the wet season a layer of rainwater just a few centimeters deep spreads across the flat — and it stays that shallow and even because the salt crust is so extraordinarily level that height varies by only centimeters across roughly 10,000 square kilometers. That extreme flatness is not just a curiosity: space agencies have used Uyuni as a calibration target for satellite altimeters, because there's almost nowhere else on the planet's surface this level to check an instrument's accuracy against.

Best time to visit

The mirror effect needs standing rainwater, so it's strongest roughly December to April, peaking January–February at dawn when the air is calm. For the classic cracked-hexagon salt-crust photos instead, visit the dry season (July–October), when the surface is solid enough to drive across freely.

Getting there

220 km from Potosí. Joya Andina International Airport (UYU) is about 89 km away.

From the encyclopaedia

Salar de Uyuni is the largest salt flat in the world, with an area of approximately 10,582 square kilometres (4,086 mi²). It is situated in southwestern Bolivia, within the Daniel Campos Province of the Potosí Department, near the crest of the Andes Mountains, at an elevation of 3,656 m (11,995 ft) above sea level.

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