On the 150th anniversary of its founding, Kevin Costner explores Yellowstone National Park to find out if it's still as wild and untouched as it was on the day of its birth, and looks back at the events that led to its preservation.

A natural history portrait of a year in Yellowstone, following the fortunes of America's wildlife icons as they face the challenges of one of the most extraordinary wildernesses on Earth.

Yellowstone is one of the most remarkable places on the planet. It’s home to North America’s most iconic wildlife, including grizzly bears, wolves, great grey owls, beavers and bison. Every year they must survive extreme weather as the thaw transforms this mountain wilderness from freezer to furnace.

Sitting on top of one of the world’s largest super-volcanos are 3,500 square miles of the most spectacular American wilderness. This summer, National Geographic Channel opens this world to you LIVE with a four-night special event. The action reaches boiling point in the world’s first National Park, Yellowstone.

Journey with Kirk Johnson to Yellowstone, where wolves, grizzlies, beavers and Great Gray owls survive one of the greatest seasonal changes on the planet. As the temperature swings 140 degrees, cameras capture how the animals cope.