What: Rocks in Death Valley occasionally seem to slide across the deserted area on their own, with no power applied and no ropes attached. How does this happen? The sailing rocks have been studied since the 1900s and scientists believe that the strange movements of these stones are the result of a perfect balance of water, ice, and wind that occurs in the winter months. Thin sheets of ice form under the stones and push them forward, when even a light wind appears.

Where: Death Valley, California, USA

When: December — February