Racetrack Playa is a lake bed which is always dry and flat covered with mudcracks and deposits of slime and clay. With a barren climate it rarely rains few inches due to which the steep mountains around produce a large amount of water runoff that transforms the clay floor of playa into a broad shallow lake.
The most interesting thing about Racetrack Playa is the sliding rocks at Playa (a dry lake bed). These rocks which weight several hundred pounds are found on the floor of the playa with long trails behind them, cutting a furrow in the sediment as they move.
There are no certain reasons yet about these moving stones but different people claim different explanations. A few people have reported seeing Racetrack Playa covered by a thin layer of ice. One idea is that water freezes around the rocks and then wind, blowing across the top of the ice, drags the ice sheet with its embedded rocks across the surface of the playa. Some other state that these stones move with strong winds but not actually been witnessed by anyone.
Racetrack stones only move once every two or three years and most tracks last for three or four years. Researchers are still curious to know the actual fact behind this nature wonder but it is still one of the most interesting mysteries of Death Valley National Park, Inyo County, California, U.S.