Sand dunes? In Colorado? Yep. And they're actually the tallest dunes in North America. Sitting in the southern half of the state 35 miles (56 kilometers) northeast of Alamosa, Great Sand Dunes National Park encompasses not only massive sand dunes, but a diverse landscape comprised of grasslands, wetlands, forestland and even alpine lakes and tundra. One of the most popular activities, summer or winter, is sandboarding, sledding or even skiing on the dunes. It's quite the experience, and you never have to worry about rocks or trees. You can also hike dunes year-round.
Like many national parks, Great Sand Dunes is usually packed with summer guests, who then clear out in the winter. Visit then (Piñon Flats Campground remains open), and you'll be treated to clear skies day and night, solitude and quiet. Yes, it's chilly during the days, but it's also usually sunny. In fact, the alpine sun can get so intense, the sand will actually feel warm. But you do still have to be prepared for subzero temps and blizzards. When you get tired of playing in the sand, you can ski or snowshoe on the nearby mountains.A final wintry treat: Mule deer and elk frequently cross the roads at this time of year [source: National Park Service].