The Howe brothers' crew builds an all-terrain wheelchair for a veteran.

The Howe twins build a vehicle for a Hollywood film.

The team tests the Riptide with disastrous consequences.

The Howe twins present the amphibious tank to the Army.

E.J. and Jeff are trapped in a pitch-black cavern surrounded by bears.

E.J. and Jeff are surrounded by lions on South Africa’s Wild Coast.

E.J. and Jeff face elephants and hippos in Botswana's Okavango Delta.

Sneak peeks are revealed as show veterans prepare for the next challenge.

Twelve veteran survivalists take on the badlands of Colombia.

Hunger, thirst and distrust threaten to wreak havoc on several competitors.

Learn about the three categories of factoring Primitive Survival Rating.

Matt Wright begins his solo XL challenge and must find a food source fast.

Matt Wright and his shelter can no longer handle the beating rain.

Matt discovers a new camp, giving him hope another tribe could be close by.

Matt reads a letter from his wife that was hidden inside a knife handle.

More determined than ever, Matt tries to hunt down the other survivalists.