No, that stone in today"s homepage image didn"t get there by itself. Or did it? Not only is Death Valley one of the hottest places on Earth, it also boasts a mysterious geologic phenomenon—rocks that drift across the exceptionally flat desert floor, seemingly under their own power. The rocks here at Death Valley"s Racetrack Playa are known as "sailing stones" and they can vary in size from a few ounces to hundreds of pounds. As seen in our image, the stones leave long trails behind them as they move across the scenic dry lakebed.