Yellowstone National Park stands as Earth's first national park and one of the world's largest intact ecosystems, straddling Wyoming, Montana, and Idaho borders. Covering 9,000 square kilometers, Yellowstone contains over 10,000 geothermal features—representing more than half of the world's total geysers. Old Faithful erupts regularly every 90 minutes, shooting water 40+ meters high, making it one of Earth's most predictable natural phenomena. The park sits atop a massive geothermal hotspot containing extraordinary geological processes visible nowhere else. Yellowstone protects grizzly bears, wolves, bison, and hundreds of other species in their largely natural habitat, making it one of North America's most significant conservation areas and attracting approximately 4 million visitors annually.