Yellowstone, widely held to be the first national park in the world, is known for its wildlife and its many geothermal features, especially Old Faithful Geyser, one of the most popular features in the park. It has many types of ecosystems, but the subalpine forest is dominant. By driving the grand loop road, visitors can view the park from the comfort of their vehicle and also take a rest at one of the many roadside picnic areas.
It is located primarily in the U.S. state of Wyoming, although it also extends into Montana and Idaho. Yellowstone National Park spans an area of 3,468.4 square miles (8,983 km²), comprising lakes, canyons, rivers and mountain ranges. Yellowstone Lake is one of the largest high-altitude lakes in North America and is centered over the Yellowstone Caldera, the largest supervolcano on the continent. The caldera is considered an active volcano. It has erupted with tremendous force several times in the last two million years.
Hundreds of species of mammals, birds, fish and reptiles have been documented, including several that are either endangered or threatened. The vast forests and grasslands also include unique species of plants. Yellowstone Park is the largest and most famous megafauna location in the Continental United States. Grizzly Bears, wolves, and free-ranging herds of bison and elk live in the park. The Yellowstone Park Bison Herd is the oldest and largest public bison herd in the United States. Yellowstone also has numerous recreational opportunities, including hiking, camping, boating, fishing and sightseeing.