Yellowstone National Park

Yellowstone is the world’s first national park and still unrivaled in geothermal spectacle, with over 10,000 features including Old Faithful. Spanning 8,983 sq km across Wyoming, Idaho, and Montana, it sits atop a supervolcano and hosts more than half of Earth’s geysers. Its 4.5 million annual visitors witness the largest free-roaming bison herd in North America, alongside wolves, grizzly bears, and wolverines. This geothermal density dwarfs that of #4 Galapagos, where volcanic activity is more sporadic and less concentrated.