Southern Colorado, s unique Great Sand Dunes rise to a height of 750 feet above the San Luis Valley floor and are the nation, s highest dunes not adjacent to an ocean or lake. The sweeping dunes were protected as a national monument in 1932 and as a national park in 2000. From prehistoric hunter-gatherers to the historic Ute Indian tribe, inhabitants have long used the resources of the land around the dunes. Zebulon Pike was the first American explorer to witness the dunes in 1807, followed by a long procession of other explorers, ranchers, and miners. Today, visitors from around the world come to climb up and slide down the dunes in Great Sand Dunes National Park and Preserve.