Although the Great Sand Dunes in Colorado were “discovered” by European explorers in the 1880s, archeologists have found evidence that there were people living in the area for at least 11,000 years. In 1932, President Hoover was alarmed when he learned that gold mining and concrete companies wanted to establish operations in the area and moved swiftly to declare it a national monument to preserve it. At the time, the park covered around 35,500 acres. President Clinton and the Congress expanded the territory in 2000 to just over 149,000 acres and declared it a National Park. Though it’s not the largest desert in North America, it has the tallest sand dunes.