Florida's brutal black water swamp pushes a hard-headed homesteader and an elite military Alpha male to their limits. Threatened by venomous snakes, dangerous wild boar and torrential rains, the clashing survivalist must work together or fail alone.

Surrounded by crocodiles, leopards and venomous snakes, survivalist band together against the South African bush. But scorpion and aggressive tick -- in the most vulnerable parts of the body -- put their challenge at risk.

A pair pushing 50 and a pair in their 20s take on the Sonoran Desert.

An Australian bushman and an American biologist form an intimate bond as they take on the Namibian desert together. The relationship grows as they search for scarce food along a thin stretch of raging river whole territorial baboons track them at every turn.

When nature calls, a fan's risky survival strategy backfires.

After surviving a nearly fatal car crash, an impulsive adventurer is paired with a cautious archaeologist in the Texas desert. Stalked by mountain lions and tarantulas, this odd couple must work together to endure scorching days and frigid nights.

All-Star survivalists Wes and Suzänne take on Ecuador's relentless rainforest. Aggressive pumas, venomous snakes and constant storms make every step dangerous. Even these veterans are not prepared for the shocking news that shakes their challenge.

Upon completing his 14-day Fan Challenge, Dan, a biologist from Hawaii, attempts 21 days in a completely foreign landscape, the blistering Chihuahua Desert. Paired with a leathersmith, he takes on rattlesnakes, stinging fire ants and bone-chilling nights.

The frigid Montana wilderness pushes the survivalists' partnership over the edge. As they struggle to work together, wildlife including bears and aggressive moose circle their camp. Plummeting temperatures create the need for drastic action.

The mile-high altitude of the Rockies tests two strangers' ability to adapt.

Torrential downpours hammer the survivalists as soon as they're dropped into the Georgia rainforest. Pushed by the weather, mountain lions, black bears and poisonous copperheads, the pair create a bond that leads to a life-changing decision.