Considered by some to be the most terrifying horror film of all time, The Exorcist redefined the horror genre, becoming a cultural phenomenon to the point where some women have been urging not to watch it when pregnant, and are since then release has become an enduring cultural classic.
While few hugely profitable films can escape a spate of sequels, those that followed The Exorcist largely fell flat (though they caved in at that moment) and never quite managed to live up to what made the original so great.
Based on the novel of the same name by William Peter Blatty, the film follows a young girl named Regan (Linda Blair) who begins to develop mysterious symptoms that no doctor can find a logical explanation for. Her mother (Ellen Burstyn) becomes increasingly disillusioned with the doctors as she is unable to come up with a reasonable answer to the condition. At the end of her wits and on the advice of one of the doctors treating Regan, her mother capitulates and seeks help to perform an exorcism on her daughter.
The conflict between science and the inexplicable is a central theme throughout the film; whatever you believe, this movie has many scenes that will make you want to call out his name for help.