3. Sanctum
Sanctum is a 3D adventure about a group of cave divers who become trapped in a complex cave system after it begins to flood following an unexpected thunderstorm, which then turns into a cyclone. The film is based on co-writer Andrew Wight's own harrowing experience while cave diving in 1988, where 13 divers became trapped in an underwater cave in much the same way as in the film. So far, so good, right? Hell, James Cameron even attached himself to the thing... The problem is that Wight assumed the real drama of his ordeal wasn't enough to sustain a film, and so introduced a needless, crass human element of conflict to proceedings. In the film, one of the characters, Carl (Ioan Gruffud), essentially turns into a psychopathic slasher film antagonist, stealing the one remaining re-breather and attacking the surviving members of the crew. It just does a horrid disservice to an event that, while not killing anyone, was nevertheless a disastrous state of affairs.