The Racetrack Playa — a barren lakebed in Death Valley National Park — is home to one of the world’s natural wonders: “sailing stones” that mysteriously meander across the dried mud, leaving tracks in their wake. Since the 1940s, these rocks have fueled wonder and speculation because no one had seen them in action — until now.
A team of U.S. scientists recorded the first observation of these boulders in motion, using GPS monitors and time-lapse photography. By meticulously tracking weather data, scientists also explained how these rocks slog across the playa. What was one of the world’s natural wonders now appears to be the perfect combination of rain, wind, ice and sun.