Great Sand Dunes National Park

About four hours southwest of Denver, the tallest dunes in North America rise straight off the San Luis Valley floor against the snowy Sangre de Cristo Mountains. Each spring Medano Creek spreads across the sand at their base and turns it into a beach, its waves pulsing downstream every twenty seconds or so as natural sand dams build and burst. The dune faces double as a downhill run for sandboarders, and after dark the park earns its International Dark Sky designation. Late May to early June is the sweet spot, when the creek is running and the sand is still cool underfoot.