Dashing through the sand dunes at one of America's most surreal national parks

Photo: Daniel Schwen/500px

A man kicks up sand behind him as he dashes down the side of a dune on a hot June day in Sand Dunes National Park and Preserve, an 150,000-acre government-protected sandbox in southern Colorado. Though it's known for its sand dunes — the largest in North America — the park also contains a diversity of ecosystems.