Mammoth Cave National Park, Kentucky, USA, encompasses part of Mammoth- Flintridge Cave System the longest cave system in the world. It is over twice as long as the second largest cave system, Mexico's Sac Actun underwater cave.
presidents George Washington, Thomas Jefferson, Theodore Roosevelt and Abraham Lincoln are sculpted on Mount Rushmore National Memorial in the Black Hills region of South Dakota, U. National Park Service photo taken on April
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.