Yellowstone contains the world’s greatest concentration of geothermal features. These are natural features that are heated by energy from inside Earth. In Yellowstone that energy is in the form of a dome of magma, or molten rock, that is just below the surface. The park is in a region that has had active volcanoes and earthquakes for tens of millions of years.
There are about 10,000 hot springs in the park. Visitors can see hot streams, hot waterfalls, and hot pools, as well as fumaroles (steam vents), paint pots (colorful pools of boiling mud), and geysers. Old Faithful is the best-known geyser. It earned its name for its reliable eruptions. Every 33 to 120 minutes, Old Faithful shoots hot water and steam more than 100 feet (30 meters) into the air.
In addition to the geothermal features, visitors may see a spectacular canyon and waterfalls along the Yellowstone River. Other interesting sights are the park’s hardened lava flows and a volcanic-glass mountain.
Yellowstone is open year-round. The park offers programs for visitors of all ages. Boating and fishing are allowed on the lakes and rivers, but visitors must have a permit to do so.
