Sailing rocks refer to a geological phenomenon where rocks move and inscribe long trails along a smooth valley floor without human or animal involvement. Trails from these types of moving rocks are actually identified and investigated in different locations, which includes Little Bonnie Claire Playa in Nevada, and most notably Racetrack Playa, Death Valley National Park, California where the number and length of trails are impressive. At Racetrack Playa, these trails have been studied since the early 1900s, yet the origins of rock movement are not confirmed and remain the subject of research for which several hypotheses exist.
The rocks move only every two or three years and almost all trails build up over three or four years. Rocks with rough bottoms keep straight striated trails while those that have smooth bottoms tend to travel. Rocks occasionally turn over, exposing another edge to the ground and leaving a different trail in the rock's wake.