Released in 1973, to the outrage of the church and upholders of public decency worldwide, then banned on video for donkeys' years, this is a movie that's achieved cult status amongst people who've never even seen it. Groundbreaking stuff in its day, without a doubt, it's the allegedly true tale of pubescent demonic posession with, controversially, a 14-year-old playing the unfortunate victim. The most infamous scenes - bright green projectile vomit, masturbation with a crucifix, the 360 degree head twist etc - are certainly shocking, but technically shabby by today's standards. Definitely disturbing and certainly Not Very Nice, but it might not have the same impact on a modern, anaethetised audience.