Monsters of all kinds have fascinated humanity for millennia, oftentimes as an explanation for some of the world's most confounding ills and sources of fear. From sabertooth tigers painted on cave walls to modern interpretations of vampires, aliens, werewolves, and demons, all of which have proven impervious to the march of time.

As cinema creeps forward with a revamped interest in the horror genre in the 2020s, it's appropriate to look back on the greatest monster movies of all time. While one could consider any non-human entity a "monster", this list is an attempt at representing some of the most well-known and highly-acclaimed monster movies from several of the most popular horror sub-genres. While each horror subgenre could be broken out into its own list, a la the 10 best werewolf movies of all time, the list below attempts to collect the best of the best.

20 Infested (Vermines)

The 2023 French Horror Film Features Fast, Deadly Spiders

While much of the list is composed of horror phenomenons and cult classics, it starts with a brand-new entry into the monster movie pantheon. From French director Sébastien Vanicek, the 2023 movie Vermines (known in English as Infested) follows a young man fascinated with exotic animals and insects who buys a spider at a bazaar and brings it back to his apartment complex. The spider escapes the box he keeps it in and grows and reproduces at an astounding rate, with subsequent generations that are far larger, faster, and deadlier.

Plenty of horror movies have preyed on the common fear of spiders, but Infested acts as one of the best depictions of what people hate about the eight-legged insects. The spiders in Infested are extremely fast, extremely large, and have a penchant for entering a person's body in order to reproduce. This movie is unwatchable for anyone suffering from legitimate arachnophobia, and even if you have no problem with spiders, this one will get under your skin.

19 Attack the Block

The 2011 British Horror Comedy Features Alien Invaders In South London

British horror comedy Attack the Block is notable for its smart social commentary and as the debut movie for John Boyega, but the real stars are the alien invaders. The truly unique, furry, gorilla-shaped extraterrestrials look simultaneously goofy and terrifying, and help make the entire movie more fun. Boyega and Jodie Whittaker (Doctor Who's Thirteenth Doctor) are both excellent in the movie, and while the movie was considered a box office flop upon its release, the fame of Boyega and Whittaker led to more people revisiting it, earning it true cult classic status.

18 Tremors

The 1990 American Horror Comedy Introduced The Iconic Worm Monsters

The original Tremors kicked off a long-running franchise of sequels and TV shows that were middling at best, but the original has stood the test of time as a great horror comedy. Starring Kevin Bacon and featuring Reba McEntire, Tremors pits its characters against massive, flesh-eating worms in the Sierra Nevada mountains. The 1990 original creature feature has held up well over the years, with entertaining action, a memorable monster design in the "graboid", and early Kevin Bacon enjoying himself on screen. It's firmly in the "dumb fun" realm for monster movies, but few movies execute that concept better.

17 The Babadook

The 2014 Australian Psychological Horror Explored Grief And Parenting

The Babadook makes for a watch that is both frustrating and terrifying, but it's powerful no matter how it is viewed. The Australian horror follows a widowed mother and her young son as they are plagued by a humanoid monster that dwells in their basement and torments them. The Babadook acts as a powerful allegory for grief and the difficulties of parenting, and is driven by the powerhouse performance of its leads, in Essie Davis and Noah Wiseman.

The Babadook is one of the most universally-revered movies on this list, as it has a 98% Rotten Tomatoes Tomatometer score 10 years after its release. The Babadook himself has grown in popularity as a viral internet meme, and in recent years the haunting creature has even developed into an unofficial LGBTQ icon thanks to a popular internet theory that the creature is actually gay. The Babadook is deserving of a place on this list given its cult status and lasting legacy.

16 Cloverfield

The 2008 American Found Footage Horror Featured A Massive, Mysterious Monster

Cloverfield took the internet by storm in 2008, as it leaned heavily on viral internet marketing to build hype around the movie's mysterious plot and the monster that was ultimately at its center, known as "Clover" colloquially. Nowadays, the found footage horror subgenre can feel played out, but Cloverfield still manages to be as impactful now as it was when it was released thanks to its masterful balance of obfuscated scares, compelling performances, and smart monster mystery. Cloverfield was and is a truly revelatory twist on both found footage and kaiju horror, which is why it's on this list.

15 The Wolf Man

The 1941 American Gothic Horror Is A Cornerstone Of The Universal Monster Franchise

The Wolf Man is absolutely loaded with stars from the days of black-and-white cinema, and includes iconic horror icons like Claude Rains, Bela Lugosi, and Lon Chaney, Jr. The second-generation actor Chaney, Jr. is captivating both in and out of his Wolf Man visage, which is some of the finest prosthetic and makeup work of the era. Once the claws come out, The Wolf Man is at its best. The now-familiar and oft-referenced story of an evil curse plays out with perfect pacing and just the right amount of dread to create a masterful atmospheric horror.

14 Annihilation

The 2018 Sci-Fi Horror Addresses Humanity's Inclination For Self-Destruction

An argument can certainly be made for Annihilation as one of the best pure sci-fi-movies of the 21st century, and it's tough to come up with a better choice for the best sci-fi horror movie of the last few decades. At the heart of what turns out to be an alien movie is an engrossing story from writer/director Alex Garland (Civil War) that features a number of monsters that are distorted versions of typically normal animals. Dripping with tension and dread, Annihilation features powerful performances from its A-list cast and a confounding, haunting finale that will stick with viewers.

13 It Follows

The 2014 American Horror Is A Modern Cult Classic

It Follows features modern scream queen Maika Monroe (Longlegs) in her breakout role as Jay, a young girl who is constantly stalked by a malevolent entity that never moves faster than a slow walk. Monroe is tremendous, but the real star of It Follows is writer/director David Robert Mitchell. The high-concept horror is marked by its nondescript temporal setting, unsettling score, and perfectly earned jump scares, all executed through the lens of Mitchell's well-defined vision and atmosphere. Even the most seasoned horror veterans will be haunted by the simple yet sinister imagery of It Follows.

12 Creature From the Black Lagoon

The 1954 American Horror Classic Features One Of Cinema's Most Recognizable Monsters

Although he first surfaced more than two decades after the earliest Universal Monsters, the Gill-man of Creature From the Black Lagoon is one of the most visually recognizable monsters in American cinema. Part of what makes the Gill-man such a lasting and memorable monster is the fact that he is in no way evil; rather, he is a creature lost in time who defends his home from what he perceives to be invaders. The Gill-man's design and suit still holds up against modern effects scrutiny, and the story stands up spectacularly as a pure representation of 1950s creature horror.

11 The Fly

The 1986 Sci-Fi Classic Is A Foundational Body Horror Movie

David Cronenberg's sci-fi body horror about an experiment gone wrong is one of the few movies on this list to actually win an Academy Award. Special effects and makeup artists Chris Walas and Stephan Dupuis shared the award for the work they did in transforming Jeff Goldblum into the creature known as "Brundlefly", which is the final form of his character, Seth Brundle, as he slowly evolves into a human-fly hybrid. Body horror has always been hit or miss through the years, but The Fly is the finest example of the subgenre.