Yellowstone National Park was the first national park established in the world. It is located primarily in Wyoming but extends into Idaho and Montana. Yellowstone encompasses 3,468 square miles (8,989 sq km) and includes canyons, rivers, waterfalls, lakes, mountains, and many different geothermal features.
Yellowstone is known for its wildlife and spectacular scenery, but it is probably most known for the unusual and unique geothermal features. In particular, it is most notably known for the geyser Old Faithful that erupts consistently day in and day out.