Great Sand Dunes National Park and Preserve protects a striking landscape at the eastern edge of Colorado’s San Luis Valley, where the tallest dune field in North America rises beside the Sangre de Cristo Range. Established as a national monument in 1932 and expanded into a national park and preserve in 2004, it encompasses dunes, sand sheets, a sabkha, and mountain watersheds. Human presence in the valley reaches back about 11,000 years, including long ties for Indigenous peoples and later visits by European and American explorers. Preservation efforts grew from fears of industrial damage, helping secure lasting protection for one of Colorado’s most distinctive landscapes.