Native Americans have lived in Yellowstone for almost 11,000 years, and its natural beauties entice tourists from across the world.
Arizona's Grand Canyon offers thrilling activities like hiking and Colorado River whitewater rafting.
Little over 170 miles east of San Francisco, Yosemite National Park has mountains, meadows, sequoia trees, and waterfalls.
The largest Hawaiian island has rainforest and five volcanoes, some of which are active.
Maine's forests provide many adventures.
Traveling to Sedona, Arizona, requires strong shoes.