Sand dunes usually feel like the quietest places on Earth. Just wind, heat, and endless grains slipping underfoot. Yet in a few deserts around the world, dunes suddenly do something uncanny. They hum, ...

In some places, sand dunes protect shorelines from the onslaught of ocean waves. In other places, the dunes themselves are on the move, and threaten human structures. Host Flora Lichtman talks with ...

Last summer, Stephanie McNamara got her first glimpse of Great Sand Dunes National Park and Preserve in southern Colorado. The park is a monument to sand, where dunes stretch across 30 square miles ...