Most movies offer audiences an escape from the problems in their lives - a momentary distraction from all that is wrong in the world where they can fantasize about what life would be like if they had superpowers (or at the very least, something better than a nine to five job sitting in an office).
But not all filmmakers are happy with crafting escapism, preferring instead to dwell in those dark recesses of human behaviour and imagination where most people fear to tread. For them, movies aren't about getting away from reality, but rather reflecting reailty at its cruelest and most ruthless and holding up a mirror to the evils of the world.
Their films are transgressive and uncompromising, deliberately challenging our comfortable lives and asking the toughest questions about what it is to be human.
Sometimes disturbing movies depict psychopathic killers or sexual sadists; others prefer to focus on what happens inside the fog of war when morality has been abandoned and the cruelest men are given unlimited power. All of them are incredibly difficult to watch, and even the toughest movie buff will struggle to make it to the end credits.