This national park is a unique experience (as many national parks are – duh). This is an area in south central to southwest CO where the tallest dunes in North America are the centerpiece in a diverse landscape of grasslands, wetlands, conifer and aspen forests, alpine lakes, and tundra. The dunes get as high as 750 feet and are very impressive, especially from the creek bed. That creek bed into which the creek seeps over the early summer is also sand 350 feet down. So, just think, 1,000 feet of vertical sand! If you are interested in how these dunes are formed just click here. This San Luis Valley is really quite fascinating.