America's first and greatest national park. And it saved the best for last. Yellowstone was established in 1872 — the world's first national park, a revolutionary idea that the most spectacular places on earth should be preserved forever for all people. More than 150 years later it remains the gold standard. The crown jewel. The park that started it all. And spectacular doesn't even begin to cover it. Yellowstone sits atop one of the most powerful geothermal systems on earth — a churning underground furnace that heats more than 10,000 hot springs, mud pots, and geysers. Old Faithful erupts every 90 minutes like clockwork, sending 8,400 gallons of boiling water 185 feet into the Wyoming sky. The Grand Prismatic Spring glows in impossible rainbow colors visible from space. The Grand Canyon of the Yellowstone drops 1,000 feet to a thundering waterfall that turns gold in the afternoon light. And then there's the wildlife. Massive bison herds roam the Lamar Valley in numbers that shake the ground. Wolves howl at dawn in the Hayden Valley. Grizzly bears fish the rivers. Elk bugle across the meadows at dusk. Yellowstone has more wildlife per square mile than anywhere else in the continental United States. Your virtual marathon follows the Grand Loop Road through the crown jewel of the American West. Past Old Faithful. Past the Grand Prismatic Spring. Past the thundering falls. Through the valleys where the wild things roam. 26.2 miles through the park that started it all. The crown of the West is waiting.