Racetrack playa is the expanse of the lake is very flat and almost always dry. Kira-Kira has a length of 4km (2.5 miles - north to south) and a width of approximately 2km (1.25 miles - east to west). Its surface is covered by mud cracks and sendimen made of mud and clay.
One of the most interesting mysteries of Death Valley National Park is a rock slide on Racetrack Playa. These rocks can be found on the floor of the former playa with no trace behind them. Somehow these stones glide across the playa, leaving grooves in the sediment as they move. Some rocks weigh several hundred pounds.
No one knows to know exactly how the rocks move although some people have come up with some pretty good explanations. The reason why their movement remains a mystery, no one has ever seen them in motion.
Lines form behind a rock show that they move during a time when the floor is covered with mud Racetrack Playa is very soft. Lack of interference is left around the mud roads of stone animals eliminates the possibility of human or encourage or assist the movement of rocks.
