Flat to within a metre across 10,000 km2, and a mirror 129 km wide when it rains
The largest salt flat on Earth, 10,500 square kilometres of it, left behind when the last of a chain of prehistoric lakes dried out; the big one, Lake Minchin, was here 30,000 to 42,000 years ago. It is so flat that the elevation varies by under a metre across the whole thing, which is why satellite teams use it to calibrate Earth-observation instruments. In the wet season, December to April, a few centimetres of dead-calm water sits on top and turns it into a mirror 129 km across, with no horizon and no way to tell which way is up in a photograph. Underneath is Bolivia’s other claim on the future: about 23 million tonnes of lithium resources as of 2024, roughly 22 percent of the world total. Potosí Department, reached from the town of Uyuni.
Potosí Department, Bolivia
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