Bear Grylls reviews how realistic survival movies are, including The Revenant, Cast Away, Point Break, Titanic, Bird Box, and more. Bear talks about his experience sleeping inside the carcass of a camel, dealing with a malfunctioning parachute, and almost freezing to death. Bear Grylls hosts Nat Geo's six-part series Hostile Planet, premiering April 1, at 9/8c.