The Sailing Stones

The sailing stonesĀ also referred to as sliding rocks or moving rocks, are a geological puzzling phenomenon found in California, Death Valley. These rocks, some as heavy as 300 Kilograms, are mysteriously transported across a virtually flat desert plain without human or animal intervention, leaving erratic trails in the hard mud behind them, some hundreds of yards long. They move by some mysterious force, and in the nine decades since we have known about them, no-one has ever seen them in motion.

The Sailing Stones ~ http://ourbeautifulworldanduniverse.com/the-sailing-stones.html