Bear Grylls enters the forest of Transylvania, where he encounters steep ravines, an underground water system and an adult brown bear.

Bear goes to Texas and navigates a desert and deep gorges and encounters a diamondback rattlesnake.

Bear fights his way across the frozen wastelands of North America's Yukon.

Bear tries to survive the rugged West Coast of Ireland, where he must scale 2,000-foot-high sea cliffs.

Bear tackles the deadly mangrove swamps and infamous viper habitats of Panama.

Bear choppers into petrified swamps devastated by the 2004 tsunami and has to navigate his way out, facing killer lizards, snakes, waterfalls and sheer cliffs.

Bear advises how to survive on a deserted island without food or running water.

Bear Grylls takes on Hell's Canyon in Oregon, where snowdrifts, frozen lakes, burnt-out forests, and frigid white-water rapids await.

Bear Grylls survives the deadly swamps of the Deep South.

Mountaineer Bear Grylls profiles Hawaii's Kilauea volcano.

Bear Grylls draws upon his experiences to survive the Costa Rican rain forest.

Bear uses his knowledge of American Indian survival techniques in the Sierra Nevada.

Bear Grylls faces the heat in Moab, Utah.

Bear heads to the Arctic Circle, where he encounters a frozen waterfall, wild reindeer and some of the coldest conditions on the planet.

Bear travels to Alabama, where he takes on white water, comes face to face with a wild boar and braves a raging forest fire.

Bear puts his survival skills to the test in the blistering heat of the Sahara Desert.

Bear puts his survival skills to the test in the blistering heat of the Sahara Desert.

Bear Grylls demonstrates how to survive hurricane season in the Dominican Republic.

Bear Grylls travels to the desert of Mexico's Baja California, battling a bee sting and a deadly diamondback.

Bear continues his travels in the Sanyan mountains of Siberia where he meets the Tuvans, who have lived there for 20,000 years; he eats squirrel and swims naked through icy water to illustrate survival techniques.

Bear Grylls parachutes into the Siberian tundra, one of the coldest and harshest places on Earth.

Famed survivalist Bear Grylls says goodbye to Hollywood and takes celebrities on journeys into some of the wildest locations in the United States and around the world. Whether it's searching for food in the most remote environments or battling intense weather, each episode chronicles the celebrity's experience of pushing their body and mind to the limit to successfully complete the adventure.

Surviving in the wild is not an exact science. Beyond the basics of finding water, food, shelter and eventually help, opinions vary. Two experts tell how they think it's done in this series, as initial episodes feature trained survivalists Dave Canterbury and Cody Lundin demonstrating the skills and creative thinking that can help one cope in tough surroundings. Equipped with minimal gear, the pair are left in remote locations -- an uninhabited island off Nova Scotia, a New Zealand mountaintop, deep in the Everglades, the jungle of Thailand, and the desert of Baja California, to name a few -- where they battle the elements and sometimes each other. Season 3 introduces U.S. Special Ops veteran Joseph Teti to replace Canterbury, in the middle of Season 4 primitive survivalist Matt Graham of Discovery's "Dude, You're Screwed" replaces Lundin, and partway through Season 5 producers forge new partnerships by rotating survival experts as hosts.

Teamwork in a survival situation is of utmost importance. But what happens if the team consists of a mismatched husband and wife, trying to survive in harsh outdoor conditions while rarely seeing eye to eye? That's the scenario in "Man, Woman, Wild," which features former Special Forces survival expert Mykel Hawke and his wife, Ruth, a journalist, who are plunked in a remote location for four days and nights. From building a shelter to hunting for food to finding a way out, Mykel and Ruth must find common ground as he teaches her the skills to survive in the wildest places on Earth.

Discovery Channel takes the ubiquitous survival show theme to the next level by stripping it to its bare essentials. In "Naked and Afraid," complete strangers -- usually a man and a woman -- meet in a very unique way: They're stranded in a dangerous, desolate location, without food or water, and they're completely naked. Each episode follows the adventurers as they attempt to survive on their own with nothing but a personal item and the knowledge that the only prize is their pride and sense of accomplishment. Because there is no other choice, competitors quickly get to know one another -- and their surroundings -- and hope that their instincts, survival skills and intestinal fortitude serve them well.

Extreme survivalists go head to head in a race across the Alaska wild. Using ingenuity, experience and just the gear they can carry in their packs, the participants have 60 hours to reach the finish point of each leg of the adventure -- the series features 13 legs -- and in addition to navigating treacherous glaciated river valleys, barren ridgelines, and high mountain peaks, the challengers battle hunger, dangerous predators and unpredictable weather. There is no grand prize awaiting each leg's winner, other than the pride of accomplishing a grueling feat. For season three, the 12 competitors are divided equally into four teams -- Military, Endurance, Alaskans and Lower 48.

TV's most extreme survival challenge just grew extra-large. Veteran survivalists familiar with the stripped-down drill after appearing on "Naked and Afraid" attempt to survive in a desolate, dangerous environment for 40 days -- 19 more than they previously experienced on the show. Pushing the very limits of human endurance, the men and women must all vie for the same limited food, water and shelter while avoiding territorial-sensitive predators and venom-filled reptiles. Because there is no other choice, the competitors quickly get to know one another -- and their surroundings -- and hope that their instincts, survival skills and intestinal fortitude serve them well.

Surviving in a remote outdoor location is no game, but elite outdoorsmen turn it into one in this series. In each episode, one of the participants is captured by the other four, blindfolded, dropped in a harsh, unforgiving environment -- think dense jungle, frigid glacier or rollicking sea -- and given 100 hours to find civilization, or the game is over. The other players monitor and comment on his progress from a nearby command center. The players include Terry Schappert, a master sergeant in the U.S. Army Special Forces; John Hudson, a U.K. Royal Air Force extreme survival instructor; Matt Graham, a primitive skills survivalist; former Navy SEAL Jake Zweig; and Casey Anderson, a wildlife tracker and conservationist.

The breathtaking beauty of Alaska sometimes hides the fact its winters can be incredibly harsh, especially for those who live in the state's outlying areas. "Alaska: The Last Frontier" perfectly illustrates this reality, as the series profiles life for the Kilcher family in the isolated community of Homer. For four generations the Kilchers have lived off what their 600-acre homestead has provided, but cultivating that living is never easy. Led by patriarch Atz Kilcher and his brother Otto, the family spends the short summer and fall gardening, hunting and fishing for food, gathering supplies from the land and preparing their animals for the winter. Viewers, who may or may not have a fancy phone by their side while watching on their big-screen high-def TV, also see the Kilchers living off the grid, where running water and electricity aren't daily staples, nor is contact with the outside world. Atz, by the way, is the father of music superstar Jewel.

Money and goods mean nothing to the people in "Live Free or Die." The series depicts a trend called "rewilding" -- the undomestication of humans -- and follows those who've rejected a mainstream existence to live off the land, in simple homes without electricity or running water. Being self-sufficient is a constant challenge, as obstacles like brutal weather and depleted food stocks require quick, innovative solutions. Modern pioneers include Colbert, a former financial adviser now living in a Georgia swamp; Gabriel, whose California lifestyle alternates between the mountains and the sea; and Tony and Amelia, who turned a hillside in the Blue Ridge Mountains into a garden.