Great Sand Dunes contains the tallest sand dunes in North America — Star Dune and Hidden Dune both top 750 ft of relief from the Medano Creek floodplain — set against the Sangre de Cristo Mountains in southern Colorado. The dunes formed when prevailing southwesterly winds funneled sand into a natural pocket against the mountains, where it has accumulated for at least 440,000 years. Spring snowmelt creates Medano Creek, a wide, shallow stream that flows along the dunes' east edge from late April through early July with surge waves — a phenomenon found in only a handful of places worldwide. From I-25 the standard access is Exit 52 in Walsenburg, then 75 mi west on US-160 over La Veta Pass to the San Luis Valley, then north on CO-150 to the entrance. The park was redesignated from monument to national park (and preserve) in 2004.
- Tallest dunes in North America — Star Dune at ~750 ft of relief
- Medano Creek flows beside the dunes April–July with rare surge-wave phenomenon
- Park designated 2004 (formerly a national monument since 1932)
- Dune sand surface temperatures can exceed 150°F on summer afternoons
- San Luis Valley around the park is one of the largest alpine valleys in the world
