Great Sand Dunes National Park and Preserve, Colorado, USA

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Mountains of sand. Great Sand Dunes National Park and Preserve, USA

These towering hills of sand are found, not in the Sahara, but in the US state of Colorado. Here, the Great Sand Dunes National Park and Preserve protects 750ft (229m) sand dunes covering more than 30 sq miles, sitting alongside conifer forests, alpine lakes and wetlands. The 85,000-acre park and preserve also encompasses stretches of treeless tundra at the higher elevations, where it edges up against the base of the Sangre de Cristo Mountains.

Initially proclaimed a national monument in 1932 by US President Hubert Humphrey, the territory was redesignated as Great Sand Dunes National Park and Preserve on 13 September 2004, and the size of the park was quadrupled. It welcomes visitors taking part in a multitude of activities, from sandboarding down the steep dunes to hiking, camping, horse riding and mountain biking.