If you’ve only got time to look at one set of pretty and mystifying pictures today, I recommend this article, about the rolling stones of Racetrack Playa in Death Valley, California.

Though no one has ever seen it happen, the stones — many of them upwards of 25 pounds — sometimes move on their own in the night, leaving behind them trails in the sand as long as 1,500 feet. The article’s got a bunch of pictures and some possible explanations.

Via a few people, first Rob V.