Dune

   Great Sand Dunes National Park and Preserve is an American national park that conserves an area of large sand dunes up to 750 feet tall on the eastern edge of the San Luis Valley, and an adjacent national preserve in the Sandgre De Cristo Range, in south-central Colorado, United States. The park was originally designated Great Sand Dunes National Monument on March 17, 1932, by President Herbert Hoover. The original boundaries protected an area of 35,528 acres. A boundary change and redesignation as a national park and preserve was authorized on November 22, 2000, and then established on September 24, 2004. The park encompasses 107,342 acres while the preserve protects an additional 41,686 acres for a total of 149,028 acres. The recreational visitor total was 527,546 in 2019. The park contains the tallest sand dunes in North America. The dunes cover an area of about 30 square miles and are estimated to contain over 1.2 cubic miles of sand.