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.
10. Son Of Saul
For many people, Steven Spielberg's Schindler's List is the definitive film about the Holocaust. But, as Stanley Kubrick, Michael Haneke and other filmmakers have pointed out, Schindler's List is about hope - precisely the opposite of what the Holocaust truly represented about the darkest aspects of humanity.
Kubrick never got around to directing a film about the Holocaust, but if he did it's likely to have been much closer in tone to Son Of Saul, Hungarian director László Nemes directorial debut which depicts events inslde a concentration camp from the perspective of Saul Ausländer, a member of the Soderkommando. Taking place over the course of just over a day, it depicts the full horror of the Nazi extermination camps, as Saul leads unsuspecting victims into the gas chambers and cleans up the aftermath, including his recently deceased son.
Nemes frames the imagery in tight close ups which track Saul through the camp, leaving much of the atrocities to be glimpsed on the periphery of the screen. But this "less is more" approach to the subject - no doubt made out of a sensitivity to not be seen as exploitation - only heightens the feeling of despair and dread. This is the closest the Holocaust has come to receiving the "pure cinema" treatment in dedcades.