5. The Wicker Man (1973)
The movie: A little girl has gone missing on Summerisle, an isolated island off the coast of Scotland. But when Sgt Howie (Edward Woodward) arrives to investigate, the locals seem reluctant to help. They're more interested in preparing for their elaborate May Day celebrations.
Why it's scary: The Wicker Man shouldn't work. It's a mishmash of genres that throws in comedy and surreal musical numbers alongside images of utter horror. But that's why it does work. It's the inherent otherness to Summerisle, the tonally incoherent, constantly surprising, onward-creeping wrongness - amplified by the normality felt by its residents - that makes this one of the greatest pieces of 'stranger in a strange land' horror ever filmed.
4. The Thing (1982)
The movie: A shapeshifting alien stalks the inhabitants of an Antarctic research station, masquerading as one of them until it gets an opportunity to attack. John Carpenter's remake of the 1950s sci-fi The Thing From Another World ramps up the gore and the paranoia, and ends on a note of resignation, not triumph.
Why it's scary: That paranoid atmosphere, for one thing. The Thing's oppressive, one-second-from-doom vibe never lets up for a moment, amplified by brilliant, tightly-wound performances throughout. And it's impossible to over-value The Thing's ground-breaking (and award-winning) special effects work, which unleash increasingly bizarre, hybrid nightmare creatures that will stick with you for life.
3. Alien (1979)
The movie: Arguably one of the greatest science fiction movies ever made is also one of the greatest horror movies, as director Ridley Scott sends the crew of the Nostromo off to investigate a distress call from an abandoned alien spaceship as innocently as any gang of hormonal teenagers headed off to a remote cabin in the woods.
Why it's scary: There's nowhere more horribly isolated than a spaceship light years away from home. And Giger's alien is as terrifying a monster as you could wish for. The dread goes much deeper than teeth and claws. The creature represents a multilayered, bottomless pit of psychosexual horror, its very form praying on a raft of primal terrors. And the visual ambiguity of Scott's direction during the final act - during which the high-tech environments almost merge with the monster's biomechanical countenance - are a masterclass in 'What's that in the shadows?' tension.
2. Suspiria (1977)
The movie: Dance student Suzy (Jessica Harper) arrives at a prestigious German academy on the same night as one of its students is mysteriously murdered. And as she settles in to her new school, she starts to notice that things aren't quite what they should be especially where the school's director is concerned.
Why it's scary: You don't watch Suspiria for the plot. You watch it because it's a super stylish assault on the senses. Everything from its ornate set design, to its unnatural lighting. to its prog rock soundtrack is intense and bewitching. Dream-logic, nightmare horror film-making at its absolute best.
1. The Exorcist (1973)
The movie: After messing with a Ouija board, Regan (Linda Blair) starts acting weirdly. And not just acting weirdly in a normal teenage kind of way: she talks backwards, scuttles around the house like a crab, and does unspeakable things with crucifixes. Her mother calls in a couple of Catholic priests to cast out Regan's demons, but it won't be easy.
Why it's scary: It quite simply has the most evil-soaked atmosphere of any film ever made. The Exorcist is relentless in its determination to creep you out, but ignore the scares for a moment and you're still left with an exceptionally smart and sophisticated film that demands your unreserved attention and has kept people talking to this day. A bona fide cinematic masterpiece that just so happens to be an edge-of-your-seat scare-fest too.