The Bonneville Salt Flats are perfect for speed. Every year, cars and motorcycles break land speed records on the flat expanse of the Bonneville Salt Flats. It’s been a tradition for more than a century, and racers have built a thriving community around the salt races. But how did these salt flats form, and why are they disappearing now?

SALT LAKE CITY (AP) — The silvery blue waters of the Great Salt Lake sprawl across the Utah desert, having covered an area nearly the size of Delaware for much of history. For years, though, the largest natural lake west of the Mississippi River has been shrinking.