Established in 1872 as the world's first national park, Yellowstone is best known for its hot geysers (including the popular tourist stop Old Faithful) and ranger-guided treks on horseback. It's a historical landmark – Native Americans have lived in the region for thousands of years and Lewis and Clark stopped through on their expedition west – and an geographic wonder, with alpine lakes, thick forests and deep, vast canyons that span three states: Idaho, Montana, and Wyoming. It's also the best place in the nation to see wolves.

Don't Miss: Two Ocean Plateau sits in the southeastern corner of Yellowstone Lake. It is the furthest point from a road in the lower 48 and the most remote section of the park. The marsh, also called Two Ocean Pass, is where the water splits into two creeks, one of which flows to the Pacific and one to the Atlantic.