The Wave in Utah, USA, has become a popular attraction in the Coyote Buttes area of the Paria Canyon-Vermillion Cliffs Wilderness on the Utah-Arizona border. The Wave is a multi-colored chute that has been cut into a sandstone mountain.
Ice cave in the Skaftafell National Park in Iceland. Ice caves collapse and new ones form as each glacier grinds slowly towards the sea. Local guides can help you (without dying) find one. (Visit Skaftafell National Park in Iceland.