Moving stones

Sailing stones, also called sliding or crawling rocks - geological phenomenon found on the dry lake-Reystrek Playa in Death Valley in the USA. Stones move slowly on the clay bottom of the lake, as evidenced by the long tracks is theirs. Stones move on their own without the assistance of living beings, but no one has ever seen or recorded the movement of the camera. Such movement of stones were noted in several other places, but the number and length of tracks Reystrek Playa stands out among the rest.