Yellowstone National Park, founded in 1872, is the oldest in the US.Burping mud pots, bubbling fumaroles, and exploding geysers.
Wind and water shaped it over millions of years.Over 2,000 sandstone arches dot the weathered terrain. These geological oddities look like rusty horseshoes and are spectacular.
The Grand Canyon, a mile deep and up to 18 miles wide, is one of the world's most photographed natural wonders.
The nation's most visited national park attracts 11 million outdoor enthusiasts annually.
Mountain and sea merge on Mount Desert Island, where most of the park is.As one of the earliest sites in the US to observe the sunrise, Cadillac Mountain attracts early bird crowds in summer.
The deepest US lake is in the cup of an 8,000-year-old extinct volcano.
Saguaro, named for the nation's tallest cacti, embodies the Old West.Many of these majestic plants are over 50 feet tall and endure nearly 200 years.
This area has mountain, rainforest, and coastal environments.The ancient Hoh and Quinault rainforests in the shadow of Mount Olympus draw visitors.