Yellowstone National Park

As the world's first national park, Yellowstone outpaces all other parks in geothermal diversity, hosting over 10,000 features—half of all geysers on Earth—atop a 8,983 sq km supervolcano in Wyoming. This includes Old Faithful, which erupts roughly every 90 minutes. It also sustains North America's largest bison herd, numbering around 5,000, alongside wolves and grizzlies, making its ecosystem more intact than #2, Serengeti, in terms of native predator-prey balance.