Moving Stone at Racetrack Playa

A playa is a desert basin that periodically fills with water to form a shallow lake. This playa lies nearly thirty miles off the beaten track in northern Death Valley. It is called the Racetrack because stones from the surrounding mountains mysteriously move across the playa when it is wet leaving the tracks of their movement visible in the photo. Someone figured out that it was the wind which moved the stones across the mud, but the track remain visible after the playa dries.