A mysterious masked figure who dwells in the sewers beneath a famous opera house plots to... wait, do you seriously not know what this is about?
I've seen a lot of different versions of The Phantom of the Opera. Most obviously, there's the Joel Schumacher version of the corny Andrew Lloyd Webber musical. They made it into a slasher movie in the 80's. Even Dario Argento made some weirdass Argento-y vesion, complete with decapitated dwarfs, and human sized rat-men caught in giant mouse traps. All have their merits (I guess) but the best version was and always will be the silent film from 1925, an effectively moody melodrama with an iconic performance by Lon Chaney. A must-see for all horror fans, and a nice opportunity to see just how early on the grammar of horror film making was being established.