Black Christmas (1974)

Near Christmas, a group of students, belonging to a women's fraternity, begin to receive disturbing phone calls and terrible threats. One of them is murdered, another disappears and they begin to live through the horror without much help from the police. Stalked by a psychopath who sneaks into their house, and who is hiding in their attic, they will try to fight to survive. Inspired by the legend of “The Nanny and the Man Upstairs” and a series of murders in Montreal's Westmount neighborhood, this film, directed by Bob Clark, is considered one of the classics of Canadian horror cinema.