GREAT SAND DUNES NATIONAL PARK - COLORADO USA POSTCARD
- from our Affiliates
The tallest sand dunes in North America, up to 750 feet (230 m) tall, were formed by deposits of the ancient Rio Grande in the San Luis Valley. Abutting a variety of grasslands, shrublands, and wetlands, the park also has alpine lakes, six 13,000-foot mountains, and old-growth forests.