The mysterious moving rocks of Death Valley National Park, California,have puzzled scientists since the 1940s. Rocks weighing up to several hundreds of kilograms have been known to travel as for as 458 meters over the dry clay bed. Studies have shown that neither gravity nor earthquakes are responsible for the phenomenon. Some scientists believe that a combination of strong winds and surface ice account for these movements. However , this theory doesn't explain the evidence of tracks left behind by rocks, which start side by side and move in different directions. Moreover, wind speeds of hundreds of kilometers would be needed to move some of the stones. The rocks are believe to move as fast as a walking person, but so far, cameras haven't picked up pictures of a rock in motion. And no one has come up with a good explanation. Perhaps this story will remain more interesting if the real answer is never discovered.