Science Fact - 11

In Death Valley, California the rocks move along a valley floor without any human or animal intervention.

Sailing stones, sliding rocks, and moving rocks refer to a geological phenomenon in which rocks move from one place to another leaving long trails without any human or animal intervention. The trails (or tracks) may be linear or nonlinear and even two rocks which start from same position may end in totally different directions. 

Tracks from these sliding rocks have been observed in various locations, including Little Bonnie Claire Playa in Nevada, and most notably Racetrack Playa, Death Valley National Park, California where the number and length of tracks are notable. 

It has been postulated that the movement is caused due to strong winds or ice-formation on the surface of rocks  which reduces the frictional forces, however, it is difficult to find the actual reason behind the movement as the rocks move once in three-four years and the duration of movement lasts up to ten seconds.