Water is the lifeblood of the Great Sand Dunes system. Streams begin as mountain snowfields, melting then flowing through alpine lakes, forests, dunes, grasslands, and lush wetlands. Explore the mountain watershed of the Great Sand Dunes. Rugged 13,000' summits, alpine lakes, tundra, and ancient forests are protected in Great Sand Dunes National Preserve. Explore the tallest dunes in North America! Whether hiking, jumping, sliding, or exploring in a dunes wheelchair, the Great Sand Dunes are a unique wilderness area protected for all to enjoy.Great Sand Dunes National Park and Preserve is one of the most biologically and geologically diverse parks in the United States.