Great Sand Dunes National Park

The basics: Sand sledding, boarding and hiking bring people to this barren, sunny world in southern Colorado. The park contains the tallest sand dunes in North America, plus sand sheets, alpine tundra and Sangre de Cristo mountain peaks. Among the creatures that dwell there are tiger salamanders, American pikas, yellow-bellied marmots and snowshoe hares.

Visitors: 299,513 people visited the park in 2015.

Square miles: 138.

Founded: 2004.

More information: nps.gov/grsa; 1-719-378-6395.