Situated on the Yellowstone Caldera, the first national park in the world has vast geothermal areas such as hot springs and geysers, the best-known being Old Faithful and Grand Prismatic Spring. The yellow-hued Grand Canyon of the Yellowstone River has numerous waterfalls, and four mountain ranges run through the park. There are almost 60 mammal species, including the gray wolf, grizzly bear, lynx, bison, and elk.