Mystery of the moving rocks

Geologists have been able to explain much about the way the earth was formed, how its mountain ranges and basins rose and sank from shifting and stretching tectonic plates, and other formerly enduring mysetries of the ages. But there's one thing, strange and seemingly inconsequential -- albeit fascinating -- that science hasn't been able to explain.

Deep in the basin of foreboding Death Valley is a flat area locals call "The Racetrack," for one reason: rocks and boulders which dot the area seem to be engaged in a strange (and unspeakably slow) race across the dessicated mud. Long furrows in the mud are giveaways of the rocks' motion, which is usually zigzagging but sometimes form complete circles, but what puzzles experts is just how they move. Some think the wind has something to do with it -- though some of the rocks weigh as much as 700 pounds -- while others guess that rare instances of rain in Death Valley turn the basin into a slick, lubricated track that would allow the wind to move the rocks more easily.

But despite decades of research -- and even GPS tracking of individual rocks -- nobody knows for sure. For now, at least, conspiracy theorists, UFO believers and other amateur explainers (even you!) still have a shot at being right.