Racetrack Playa

Racetrack Playa, a dry lakebed in California's Death Valley National Park, is scattered with hundreds of rocks — some weighing up to 320 kilograms (700 pounds) — that leave long, sometimes hundreds-of-metres-long trails etched into the cracked mud surface behind them, as though they had been dragged. No one had ever directly observed a stone moving, despite investigation dating back to the 1940s. Proposed mechanisms over the decades ranged from powerful wind alone, to dust devils, to slick algal films reducing friction, to thick ice sheets lifting the rocks entirely off the ground — none satisfactorily explained how wind, unaided, could move objects that heavy.

Cousins Richard and James Norris, alongside planetary scientist Ralph Lorenz, founded the "Slithering Stones Research Initiative" in 2011, fitting fifteen rocks with GPS trackers and installing a high-resolution weather station and time-lapse cameras across the playa. During the winter of 2013–14, a rare combination of rainfall pooled into a shallow lake on the playa's surface, froze overnight into a thin sheet, and on 21 December 2013, the researchers watched it happen: as morning sun warmed the ice, it fractured into large floating panels which, driven by light winds of just 3–5 metres per second, pushed against the embedded rocks and slid them slowly across the mud below.

Racetrack Playa stands, alongside the Door to Hell, as one of this collection's genuine resolved cases — not through debunking a hoax or fraud, as with Loch Ness or the Winchester Mystery House's ghost story, but through patient, well-designed field science finally observing a real, entirely natural phenomenon directly. The "ice shove" mechanism the Norris team documented is well known in polar regions; Racetrack Playa simply represented the first time it had been observed moving rocks in a desert environment, a genuinely novel finding published in a peer-reviewed journal rather than left as permanent open speculation.