Hosts Jack Steward and Colton Smith get up close and personal with the massive brown bears of Katmai National Park in Alaska, home to the largest population of brown bears on the planet. The guys watch bears fish for salmon and dig for clams along the Pacific Coast and camp out in the back country surrounded by bears.

Jack and Colton experience the awesome power of Mother Nature in Alaska as they kayak with whales and sea otters through Glacier Bay National Park, witness glaciers crashing into the sea and trek to get up close to a mammoth Glacier.

Going off the beaten path takes on new meaning for Jack and Colton in the "American Alps" in North Cascades National Park in Washington, as they're pushed to the limit and forced to overcome fears in a quest to make the climb of their lives.

Mountain goats, marmots and spotted owls are just a few of the creatures that Jack and Colton meet face to face as they journey through Olympic National Park in Washington. From rainforest to rocky coast to the magnificent mountains, the guys discover why Olympic is really three parks in one.

Jack and Colton trudge through miles upon miles of volcanic ash and forge a treacherous river in search of one of the most powerful volcanoes on earth. Oh, and they are on constant alert for brown bears too.

Jack and Colton prepare for a possible encounter with grizzly bears as they head high into the Rockies and across the continental divide on their first backpacking adventure in Glacier National Park.

Hosts Jack Steward and Colton Smith have a run-in with a bear and a showdown with big horn sheep as the hit the trails and the epic Going-to-the-Sun Road of Glacier National Park.

Jack and Colton take on Old Rag, one of the most dangerous trails in Shenandoah National Park, then belay each other 110-feet straight up a rock cliff.

Hosts Jack Steward and Colton Smith creep and crawl for miles through the underground of Mammoth Cave National Park, and help researchers capture wild bats to track a deadly disease.

Jack and Colton trek miles though an icy cold river, then hold on for dear life while climbing one of Zion National Park's scariest trails.

Jack and Colton saddle up and check out the land of hoodoos, then go back country camping... ultra-light with no tent. It's just them and the creatures of the canyon floor.

Hosts Jack Steward and Colton Smith learn about the supervolcano that lies deep beneath the park and check out the hot spots it creates. Then they track the parks elusive wolves and other awesome wildlife.

Jack and Colton experience the power of the Yellowstone River at its own Grand Canyon, towering waterfalls, and white water rapids.

Jack and Colton trek through the land of giants in Sequoia National Park. Then it's a face-off with fear as they take on a 150-foot climb straight up a sheer granite rock wall.

Jack and Colton head to Death Valley National Park in search of one of the most scarce resources in the park... water.

It's a rocky ride for Colton and Jack as they explore the Chasm of Doom and climb The Eye of the Cyclops in Joshua Tree National Park.

Colton and Jack are on the island of Maui checking out Haleakala National Park. They're flying high and riding low while exploring the house of the sun.

Jack and Colton are taking on Mauna Loa, the largest volcano on Earth, battling altitude sickness and the threat of severe weather along the way.

Colton and Jack are slogging their way through the sloughs of Everglades National Park. Then it's a marathon kayak adventure out to one of the remote keys in the gulf coast.

Hosts Jack Steward and Colton Smith face off with Mother Nature in Pictured Rocks National Lakeshore, spending a cold winter in a snow trench before taking on a 70-foot wall of ice for a climb like none they've done before.

In the largest urban national park in America, the hosts try mountain biking and hit the beach for their first surfing adventure.

Hosts Jack Steward and Colton Smith relive some of their best wildlife encounters in the nation's national parks.

Camping in the national parks is always an interesting experience for Colton and Jack, especially when it comes to finding resources for food and water and a place to sleep.

From the remote wilds of Alaska to the high Rocky Mountains of Montana and Wyoming, there's one animal that draws people to the national parks. Today, Jack and Colton revisit some of their greatest bear encounters and experiences.

Colton and Jack have crisscrossed the country for some truly epic national park adventures from rafting the mighty Yellowstone River to the deep underground of Mammoth Cave and hiking to the top of the largest volcano in the world in Hawaii.