Great Sand Dunes

Declared a national park in 2004 after previously operating as a national monument, it protects the tallest sand dunes in North America, some of them over 230 metres, formed over millennia by winds that trapped sediment from an ancient dried-up lake against the foot of the Sangre de Cristo mountains. The park is home to the Great Sand Dunes toad, an endemic species that survives exclusively in the seasonal wetlands at the base of the dunes.