Situated on the Yellowstone Caldera, the park has an expansive network of geothermal areas including vividly colored hot springs, boiling mud pots, and regularly erupting geysers, the best-known being Old Faithful and Grand Prismatic Spring. The yellow-huedGrand Canyon of the Yellowstone River has a number of scenicwaterfalls, and four mountain ranges run through the park. More than 60 mammal species including gray wolves, grizzly bears, lynxes,bison, and elk, make this park one of the best wildlife viewing spots in the country.

 - Wikipedia