Although it's also known for for wolves, bison, and stunning scenery, Yellowstone National Park was established as the world's first national park in 1872 largely because of its geological wonders. In "Geology Underfoot in Yellowstone Country," author and geologist Marc Hendrix takes you to over twenty sites in the park and surrounding region that illustrate the deep-time story of Yellowstone Country, from its early existence as a seafloor hundreds of millions of years ago to an earthquake swarm in 2008 that caused some folks to wonder if the Yellowstone Volcano was going to blow its top again.