The Exorcist (1973)
Considered a cinematic masterpiece—at least in the eyes of horror movie enthusiasts and those who don’t mind losing a few days sleep—The Exorcist redefined the horror genre and sparked a deeper interest in demonology. The movie wasn’t anything new as stories of real-life exorcisms have been around since time immemorial. The validity of these accounts are debatable. Still, episodes range from the mundane (behavioral changes, hearing disembodied voices) to the extreme (convulsions, malicious intent, and an aversion to religious symbols). There are plenty of documented exorcisms to watch on YouTube... if you dare.