The best horror movies of the 21st century typically focused on people struggling to survive a dark force beyond their comprehension.

We live in scary times that can often feel like lot more unsettling than any fictional horror movie, but some of the best horror movies tap into real world terrors — and that’s especially true of the highlights from the last two decades of the genre, one of the most varied in its history. From graphic depictions of gory showdowns to subtler looks at psychological dread, the best horror movies of the 21st century typically focused on a handful of people struggling to survive a dark force beyond their comprehension. Who can’t relate to that? Here are 20 of the most potent examples, ranked from top to bottom.

20. “The Descent” (2005)

Neil Marshall’s economical monster movie takes place almost exclusively within the confines of a shadowy cave and the terrible, terrible things lurking within it. After a gradual beginning in which coworkers and friends venture into a cave during their weekend gateway in the Appalachian Mountains, the group winds up trapped in an unknown labyrinth and terrified about their prospects of finding an exit. In other words, “The Descent” is already a claustrophobic nightmare even before the monsters show up. But once they do, Marshall turns the slow-build suspense into a rollercoaster, with the survivors attacked from every corner by blind, monstrous humanoids craving blood. Using the contained setting to his advantage, Marshall makes the characters’ ceaseless terror as much a special effect as the monsters; the vivid performances draw us into the visceral quality of running and crawling from an unstoppable force that no amount of physical dexterity can possibly deter. Rooting the drama in the plight of a heroine already reeling from the death of her daughter, the movie also takes on a keen allegorical quality, as if the never-ending paths of caves represent far greater challenges taking place in the beleaguered woman’s man. Psychological thrillers never knew such evils. —EK

19. “The Mist” (2007)

There are two kinds of Stephen King adaptations: The ones that disgrace their source material, and the ones that elevate the author’s novels and short stories to stunning new heights. Frank Darabont’s “The Mist,” much like Frank Darabont’s “The Shawshank Redemption,” is definitely one of the latter. The action is confined to the sterile confines of a Maine supermarket, where local shoppers find themselves trying to make sense of the thick fog that has enveloped their town (and to survive the profoundly wretched monsters that live inside the impenetrable white clouds). As the tension grows between Thomas Jane’s decent-hearted painter and Marcia Gay Harden’s lunatic doomsayer, the film rots into a morality play about hope that eventually starts to feel like a grim response to “Children of Men.” The unforgettable final scene, which even King himself admits improves on his novella, cements “The Mist” as an unflinching battle for the dark heart of humanity — one that can’t be so easily won. — DE

18. “The Cabin in the Woods” (2012)

Ridiculously entertaining proof that you can have your cake and eat it, too, Drew Goddard’s “The Cabin in the Woods” isn’t only a very satisfying horror movie about a bunch of sexy twentysomethings who choose the wrong AirBnB, it’s also a smartly self-reflexive look at the value of horror movies themselves. Co-written by Joss Whedon (and co-starring a pre-Thor Chris Hemsworth), “The Cabin in the Woods” plays by the rules of the game even as it breaks them one-by-one — the film is as fluent in its genre as “Scream” ever was, but Goddard isn’t content to simply subvert the familiar tropes about who’s going to die and how, it uses its knowledge to confront their meaning and implicate our bloodlust. Why are we so giddy to see these kids get slaughtered? What does this sadistic covenant between storyteller and audience say about us? And why do horror stories seem to be the most pervasive of narratives, the most reliable, the most primal? More fun than it is finger-wagging, Goddard’s debut crescendoes like few movie ever have, its wild finale showing us things we could never imagine before it leaves us with a clearer view of ourselves. — DE

17. “REC” (2007)

Sorry, “Paranormal Activity”: The best found footage horror movie of the new millenium is this relentless Spanish take on the zombie genre from co-directors Jaume Balagueró and Paco Plaza, which finds a news reporter trapped in a building with doomed firefighters and fending off hordes of demonically possessed undead. Sony picked up the rights and buried it on DVD, only to release the shot-for-shot remake “Quarantine.” One can get the idea from the English language version, but the original retains its visceral immediacy, which is so jam-packed with terror that the directors sped right into a sequel that picks up where the earlier one left off. “REC 2” is worth watching for a similar thrill ride, but “REC” stands alone as a tense example of how the ambiguity of shaky cam footage isn’t an excuse for shoddy storytelling; “REC” delivers a steady stream of frights because its camera man never knows quite where to look — and by the time he figures it out, it might be too late. —EK

16. “You’re Next” (2011)

“You’re Next” didn’t break new ground in the horror genre, but it stuck to rules that work. Director Adam Wingard and screenwriter Simon Barrett have yet to do better than this tightly-wound survival story that’s replete with disarming humor to hold the whole bloody mess together. The result is like Chuck Jones by way of John Carpenter. After a morbid prologue in which two unnamed characters meet their doom at the hands of an unseen menace, “You’re Next” settles into a family reunion at an isolated vacation home deep in the woods. The affluent heads of the Crampton household, parents Paul (Rob Moran) and Barbara (Aubrey Davidson), invite their grown children and their respective significant others to a dinner party that quickly turns grim. Before the danger begins, however, Wingard and Barrett neatly set up the family dynamic. Klutzy college professor Crispian (AJ Bowen) shows up with his levelheaded girlfriend Erin (Sharni Vinson). Aimee (Amy Seimetz) brings her indie filmmaker boyfriend Tariq (horror director Ti West), while the neurotic Felix (Nicholas Tucci) has the mysterious goth Zee (Wendy Glenn) in tow. Joe Swanberg rounds out the cast as the smarmy Drake — not that you need to keep track of all of them, because the body count rises fast. Arrows stream through the window and put the entire household into shock mode.

But then the tables turn in a most exciting fashion: The murderers didn’t count on Aussie outback veteran Erin’s fast-paced survival skills. Setting traps and taking advantage of her environment (kitchen blenders have never been used this creatively before), she keeps the masked killers on their toes and shifts the power dynamic, upending the mysterious scheme behind their attack. Never taking its scares too seriously, “You’re Next” barrels forward, eager to please at every turn, and always hitting its mark. —EK

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