Geothermal features permeate the park by the thousands, to include: boiling springs, hot springs, both boiling streams and hot streams, mud pots, mud holes, geysers, thermals, cones—every facet of an active live volcano you can think of (besides the more well-known image of exploding lava), is in Yellowstone National Park.
You can easily see the instability of the earth's surface from a just casual walk around the park's most visited areas, especially at its delicate edges, because the landscape there changes and shifts all the time. New hot spots open, become dormant, or shrink and then widen very quickly, as a perfect example of how fast a landscape can alter. A wild and savage beauty, this is "The Great American West" at its finest. You have to see it.
