Colorado is known for its Rocky Mountains, skiing, and snow. But what a lot of people don’t know about Colorado is that it is home to the tallest sand dunes in North America. Great Sand Dunes National Park has almost 800-foot tall sand dunes and is located by the Rocky Mountains. And to top it off, there is a shallow creek flowing around the perimeter of the sand dunes that you have to cross in order to reach the dunes. I visited on a warm summer day, so I had a blast walking through the cool creek water. The sand dunes were so vast that it took hours to cross just a small portion of them.