A survivalist postpones her wedding to try 21 days in the Colombian jungle.

When a third survivalist crashes the challenge, tension and jealousy are just as threatening as the piranha and jaguars of the Ecuadorian rainforest. Claims that there's more going on than just survival puts everyone's challenge at risk.

Two foreigners try to become the first survivalists to endure 21 days on U.S soil. But rattlesnakes, unfamiliar terrain and plummeting temperatures threaten to send them back across the pond. Lilly from Austria and Sam from the UK team up to do battle with the New Mexico wilderness.

After surviving a near-fatal fall, an equestrian stunt rider attempts to endure 21 days in Colombia.

In an unprecedented Naked and Afraid challenge, identical twin sisters Amber and Serena, as well as brothers Warren and Thomas, are dropped in the African savannah. They take on rhinos, hyenas and a territorial leopard stalking their camp.

Legend survivalists Max and Rylie are dropped in the South African bush with two novice fans to try and survive 21 days with spitting cobras, aggressive warthogs, rhinos and leopards.

Language barriers stand between two survivalists in the South African bush.

A hunter and a farmer pool their knowledge as they attempt to survive 21 days in South Africa. But when the wildlife proves too stealthy to hunt, the survivalists take a life-threatening risk for food.

A self-proclaimed 'king of the forest' and an endurance athlete tackle the backwoods of Alabama. They secure shelter and a fire early on, but when hunger kicks in, one of them does something that's never been seen in show history.

Dropped onto a frozen Alaskan Glacier, All-Star survivalists Laura Zerra and Steven Hall scramble to stave off frostbite and hypothermia. And 7,000 miles south, two new survivalists take on a sun-scorched Brazil island, with anaconda and deadly stingray.

A survival-savvy yoga teacher and a custom knife maker tackle the brutal jungle of Colombia. Their primitive survival skills are impressive, but the deadly spiders and tics test both their courage and resilience, threatening to take them down.

On the edge of the Bermuda Triangle, an Army veteran dive master and a Cajun boat captain take on relentless thunderstorms and battle dehydration as they try navigate more than 20 miles of open ocean in the ultimate test of sink or swim.

In the relentless Colombian jungle, a mom and National Guard vet teams with a firefighter. Violent storms and hypothermic conditions force them to huddle in bat-infested caves. A special bond develops between a survivalist and a wild monkey.

Jaclyn McCaffrey and Adam Young survive in Nicaragua for battling with dehydration and freezing temperatures.

An Army mom and a U.S. marine battle alligators, snakes and mosquitoes in the Florida Everglades.

A survivor of rattlesnake, shark and bear attacks teams with Brooke, wife of "Naked and Afraid" veteran Matt Wright, in a vicious African feeding ground.

In this all-female tribe’s challenge, two veteran survivalists return to mentor two newcomers on the perils of San José Del Guaviare, Colombia, for 21 days. But, scarce food resources and torrential tropical storms take a quick toll.

In the frozen American Rockies, snow storms and freezing temperatures force the survivalists to make risky choices with their fire and food sources. An out of control blaze and toxic mushrooms put their challenge and safety at risk.

Crippled by injuries and toxic frogs, an adrenaline junkie and a self-proclaimed renaissance redneck must dig deep to try to endure 21 days in Colombia.

A workaholic mom and a loner are challenged to survive three weeks in Thailand.

Two fans are selected for a two-week long challenge in Nicaragua.

A mother of four and a country boy are dropped into the jaguar filled jungle of Belize. While they hunt for food, something is hunting them, and the mental part of the challenge gets to them both. Can they survive the jungle and themselves?

All-Star survivalists Jake Nodar and Melissa Miller take on the punishing Blackwater Swamp in Florida, which teems with poisonous snakes and aggressive alligators. When one of the survivalists becomes disorientated, local authorities are called in to conduct an all-out search.

All-stars Fernando and Dani land in a rainforest in Ecuador for their third challenge, where jaguars, caiman, anacondas and bullet ants are on the prowl; their divergent approaches to primitive survival might do them in.

In an international tribes challenge, one survivalist must cope with menstruation in the middle of the African bush.