Great Sand Dunes National Park, Colorado

They appear gradually as you approach. First, an amorphous khaki blob hugging the base of the Sangre de Cristos. Then, a tan curtain that has fallen off the rod and rumpled onto the floor. And then, about four miles south of them, they come into focus: massive, improbable, creamy peaks of sand slapped against 14,000-foot peaks.

These are the Great Sand Dunes, and photographing their ever-changing forms at sundown is an intoxicating experience.

  • &#;Photographer's Insight To truly appreciate the dunes — and to get quality images of their other-worldly designs — you need to hike a strenuous hour into the dune field. Time it for 3pm in summer, and hike back as the sunsets. The long shadows of evening accentuate every curve.