Cinema has been reaching for the stars since its birth. In 1902, Georges Méliès took us on A Trip to the Moon and we've been in love with the great beyond ever since. While some genres have come and gone, sci-fi has always retained a strong presence on the big screen, our shifting ideas of the future always ripe for new stories.
That being said, choosing the 25 best sci-fi movies ever made is a bit of a challenge. But after several sleepless nights of humming and hawing (plus a bit of time-travelling to squeeze in some extra hours), here we are. So strap in, and get ready for an epic journey. Just make sure you check the air vents for any 'unwelcome passengers'. You have air vents where you are, right? Oh.
25. A Clockwork Orange (1971)
The movie: Stanley Kubrick knew a thing or two about creating visuals that would last a lifetime, and many of the images in A Clockwork Orange are simply unforgettable. Alex and his droogs in the milk bar. Ultra-violence carried out during an enthusiastic rendition of Singin' in the Rain. Alex's wide-eyed rehabilitation. The film's commentary on crime and punishment can be difficult to watch... which is kind of the whole point.
Most iconic moment: Alex receiving a heavy dose of aversion therapy.
24. The Martian (2015)
The movie: Arriving in theaters at a time when space-set thrillers were hitting screens thick and fast, Ridley Scott managed to avoid comparisons to Interstellar and Gravity. By remaining loyal to the humor in Andy Weir's source novel, the movie ends up striking that fine line between tragedy and comedy as Matt Damon's astronaut Mark Watney finds himself stranded on Mars. It's Damon's performance that drives home the dire straits that Watney's in, delivering a killer turn mostly solo, full of wit, insight and darned impressive science.
Most iconic moment: All of Watney's efforts to cultivate a potato allotment in his camp are blown to smithereens when a storm passes through. Gutted.
23. District 9 (2009)
The movie: Neill Blomkamp's killer debut takes place thirty years in the past. After an alien ship breaks down just above earth, the new species that emerges from inside it is forced to live in a ghetto where they're frequently exploited by humans. When the government tries to forcibly evict them, operative Wikus van der Merwe (Blomkamp regular Sharlto Copley) is exposed to a biochemical that slowly changes him into one of the extraterrestrial 'prawns'. The shaky realism of the camerawork only adds to the film's considerable wallop.
Most iconic moment: Wikus gets hold of his first piece of alien weaponry, and unleashes it against a criminal gang to devastating effect.
22. Eternal Sunshine Of The Spotless Mind (2004)
The movie: Science fiction typically falls into one of two camps: slickly polished and gleaming or dystopian and grimy. Eternal Sunshine falls squarely in between, into the realm of the everyday and affordable. After breaking up with his girlfriend Clementine, Joel hires a rather ramshackle firm to scrub all memories of her from his mind. Much of the movie takes place in those memories, as we see Joel revisit personal moments before they disappear. Eternal Sunshine is the best kind of science fiction, taking us to places that don't exist, but that we recognize just the same.
Most iconic moment: Joel tries to hide Clem in a childhood memory she was never a part of, turning him into a miniaturised version of himself.
21. Invasion Of The Body Snatchers (1978)
The movie: An alien race abandon their dying world and head for earth where they duplicate and replace humans in their sleep. As people start to notice something is amiss with their loved ones they soon discover that there's little chance for escape as they too will become pod people. Crisp, pacy direction and intelligent scripting turn Jack Finney's taut novel into a low-budget masterpiece and a fantastic remake.
Most iconic moment: Donald Sutherland raises his arm slowly, points and goes "GAAAAAAAAAAH."
20. Interstellar (2014)
The movie: It's Christopher Nolan's ode to the pioneering spirit, and his cleverest, most theoretical movie yet, in which Matthew McConaughey's space pilot is tasked with finding a new home for humankind, currently stuck on a dying Earth. Interstellar's spectacular marriage of operatic spectacle with Han Zimmer's unforgettable score is worth watching for its own sake, while Nolan uses quantum physics as the basis for a mindbogglingly intelligent story that is nothing short of breathtaking.
Most iconic moment: The heart-wrenching scene in which Cooper comes to terms with how much time has passed on Earth since his expedition.
19. Jurassic Park (1993)
The movie: Messing with Dinosaur DNA and hiring incompetent IT staff was never going to end well, but at least it makes for a cracking movie. Steven Spielberg's original trek back through time is one that has been beloved by fans for decades since and has spawned several sequels, though none compare to the original. Through a mix of large, intricate puppets and ground-breaking cgi (at the time) mean the special effects feel like they haven't aged at all.
Most iconic moment: The T-rex's head appears over the side of the railing, her huge jaws grinding away on a goat carcass before letting loose her almighty maiden roar. This is the first time we see - and hear - the beast, and she's glorious.
18. Planet of the Apes (1968)
The movie: Released in 1968, the year America exploded, this lean thriller is much more than a tale of apes taking command of our beloved planet. Okay, well it is that, but scratch beneath the surface and there's loads of big hot-button topics - civil rights, racism, evolution - hidden within its B-movie stylings. Most of its praise is down to Charlton Heston's performance along with those Oscar-winning monkey masks, turning this into a peerless example of "What If?" sci-fi.
Most iconic moment: The realisation that the 'planet' is in fact, our planet.
17. The Thing (1982)
The movie: From the opening lurch of Ennio Morricone's ominous score, it's obvious that things aren't exactly rosy at this science outpost deep in the Antarctic. When a helicopter of Norwegians shooting at a dog appears shortly after, it's clear that something very bad is about to happen to Kurt Russell's crew, whose research is disrupted by the arrival of a creature that imitates its host. After killing it, of course. A heady mix of paranoia and suspense, it's one of John Carpenter's most chilling films that stands up still today due to the stellar effects work by Rob Bottin and his crew, that landed the movie its only Academy Award.
Most iconic moment: Dr. Cooper tries to revive Norris with a defibrillator, only to have his arms BITTEN OFF by Norris' chest cavity - because it has teeth.
16. Ex Machina (2015)
The movie: The strength behind Ex Machina's 'man makes human robot' story isn't the sci-fi trappings behind the conceit, because that's relatively staid and downplayed. Instead it's more of a character-led thriller that builds on a lingering sense of uncertainty. Its small cast - creator, robot and guest - keep things tense and claustrophobic with strong performances from all, as you try to guess what's coming next. It's not so much a film with a twist as a situation that's hard to read; keeping you squirming as you try to second guess which way it's going to break.
Most iconic moment: Nathan (Oscar Isaac) dances away his troubles with one of his androids. Gorgeously shot in crimson shadows, it's a terrific spot of foreshadowing.