Colorado has four national parks – Rocky Mountain, Black Canyon of the Gunnison, Great Sand Dunes, and Mesa Verde. Rocky Mountain is by far the biggest, most popular, and most accessible, at just an hour and a half from Denver. It has over 350 miles of trails, is home to the highest paved road in the country, and has tons of spots for kayaking, cycling, whitewater rafting, horseback riding, and more. Black Canyon of the Gunnison, on the other hand, is one of the least visited national parks in the country. Most visitors drive, camp, and hike along the rim, although experienced backpackers can obtain a wilderness permit to explore the inner canyon. In Great Sand Dunes, you’ll seriously question whether you’re in the U.S. or the Sahara. The main things to do in the park are to climb up the sand dunes and hike, sled, or sandboard back down. Backcountry permits are also available for hiking and camping among the dunes. Mesa Verde exists primarily to protect the 5,000 Pueblo archeological sites in the area, which are among the best-preserved in the country. Scenic drives and hiking trails pass by cliff dwellings and other archeological sites, some of which can be visited on a guided tour, and the park also has its own museum.