The origin of these unique rock trails in a remote desert basin remained a mystery for centuries. Some theorized they were created by hurricane-force winds pushing rocks across slick mud, while the more superstitious believed ghosts or aliens were behind the strange sailing stones. After several decades of study, the rocks were observed in motion in the winter of 2013 — pushed along by floating ice sheets in the flooded playa. Visiting this location requires significant off-road travel deep in Death Valley National Park.