The White Sands National Monument in New Mexico is truly unique.
It is the largest gypsum dunefield on the planet. Gypsum dissolves in water, unlike normal sand, so it tends to get washed away. But in this one spot, the climate is dry enough that the gypsum sand has spread over 275 square miles.
Filmmaker Harun Mehmedinović captured this time-lapse footage, which reveals that the gypsum dunes move in waves, like a dry ocean.
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