This is the biggest mirror on EarthS

This guy is standing on the flattest, shiniest place on Earth. It takes over a large section of Bolivia, and it's so flat, dry, and reflective, that it's used for satellite calibration.

If you ever travel to Bolivia, and want to take pictures that will freak out your friends, go to the Salar de Uyuni. Because of an interesting confluence of geography and physics, this place has formed the world's largest mirror. The area forms the endpoints of major rivers, as it's one of the many wide basins between mountains. Rivers pick up sediment and minerals that they usually take to the sea. As these don't reach the sea, they deposit tens of thousands of years of salt in the basin, giving it a salty crust a few meters thick. As more water seeps into the basin and across the Salar de Uyuni, the salt is dissolved. The water evaporates slowly, until the salt is exposed, leaving an incredibly flat surface. When the next sheet of water covers that surface, it makes a bigger, better mirror than any other on Earth.

This is the biggest mirror on EarthS

The salt flats aren't just sought out by tourists. They are more level than oceans, and have better weather conditions. Because of this, they're used by space agencies for satellite calibration over long distances. Modern satellites have ruined the mystique of the Salar de Uyuni, though. They've proved that, even at its flattest, it has valleys and hills that measure in millimeters. You might as well take a vacation in the Alps.

Image: Yoshi Vic

Via NASA and Summit Post.