10 works of fantasy that are really science fiction

Sometimes you're immersed to your eyeballs in a story about supernatural monsters, or medieval lands full of eldrich gods - when suddenly, you realize the whole damn story is really about science or an alien planet full of advanced technology.

You thought you were in the realm of fantasy, but instead you found yourself suddenly in the realm of science fiction. Here are ten stories that seem like fantasy at first, but the science fiction creeps up on you.

There may be a few minor spoilers here, so beware.

A special note, for those of you who are about to say any one of the following: "Arguing about the difference between science fiction and fantasy is dumb;" "I never thought any of these stories was fantasy to begin with;" "You are saying that science fiction is better than fantasy or vice versa." Allow me to retort. I love both science fiction and fantasy, and I am also a complete nerd when it comes to genre. I love to categorize narratives because that's just how my brain works. It's fun to figure out when the edge of one genre bleeds over into another, and that's the whole point of this post.

1. The Steel Remains, by Richard K. Morgan
This hard-hitting fantasy tale of a man and his seriously badass sword-fighting abilities seems like your standard fantasy fare. It's full of castles and kings and different "races" of elves and humans and such. Until you start to realize that those elf-like guys are actually connected to something that isn't so much a magical place as it is a crashed spaceship. This novel is of the most satisfying genre-benders out there, and luckily for us the sequel (The Cold Commands) comes out this summer.

2. Lord Valentine's Castle, by Robert Silverberg
In 1980, celebrated scifi author Silverberg put out a book that looked like nothing so much as an epic fantasy. A young hero on a world just entering Renaissance-level industry has lost his memory, but is haunted by what seem to be prophetic dreams. He takes up with a ragtag group of performers to find his destiny. And yet this entire RenFaire style quest is set on a planet that's being colonized by aliens. The regular folks may not have space technologies, but they're aware of distant, gleaming cities graced with advanced tech - and of course, aliens are part of society on every level. It's one of Silverberg's best novels, in part because of the deft way he builds a world that's fantasy out the outside and science fiction underneath.

3. Thor (movie)
What could get more fantasy-ish than Thor? The guy is a god from a sparkly floating land called Asgard. He hangs out with other gods and battles giants and has a magical hammer. And yet somehow Kenneth Branagh's film version of Thor managed to give us a scifi twist on the old mythos - with a lot of help from a great script by Edward Ashley Miller and Zack Stentz - making Asgard another planet where science and magic are indistinguishable.

4. World War Z, by Max Brooks
I'm going to let World War Z take pride of place among a ton of recent zombie tales, from Mira Grant's Feed to 28 Days Later and Walking Dead, where zombies are the products of science rather than magic. These days, zombies are more likely to be plague victims than supernatural, and nothing captures this trend better than Brooks' classic "chronicle of the zombie war," World War Z. Brooks takes a classic horror fantasy and turns it into a contemporary, surprisingly realistic look at the way war and disease can turn ordinary humans into monsters - and heroes.

5. Sarah Canary, by Karen Joy Fowler
This incredible novel of nineteenth century California by the author of The Jane Austin Book Club seems at first to be the story of an inexplicably indestructible mute woman roaming through railroad camps, lunatic asylums, miner's tents, and suffragette meetings - all without being harmed or (in some cases) noticed at all. Is she a ghost? A sorceress? Fey? As the story unfolds, and our mute heroine falls in with an unlikely group of allies on their way to San Francisco, you begin to suspect there may be alien technology at work - or hey, maybe not. One of Fowler's sly tricks is to evoke a fantastical character in a historical period so weird that it might as well been another planet.

6. Inversions, by Iain M. Banks
This Culture novel is a huge departure from the usual astropolitics and AI warmaking of the other books in Banks' series. For a terrifically long time, we are immersed in the story of an incredibly clever doctor who works for a medieval-style king, attempting to get him to modernize his ways (and maybe sleep with her too). But when our doctor is nearly killed, she's miraculously saved by what her assistant thinks is magic - and we know is some kind of drone technology she's been keeping with her for protection. She's one of two Culture agents who've gone native on a medieval world, and we're swept into the fantasy setting knowing all the while that the AIs wait just a few lightyears away, waiting to swoop in and remove our characters as soon as they're sick of patriarchy and bloodlust.

7. Dragonriders of Pern series
The first few books in this series feel like flat-out fantasy. People ride dragons with whom they have a psychic link, protecting their keeps from deadly, perhaps magical "thread" that falls from the "red sun" and kills anything in its path. But the more you read the series, the more the truth comes out: Our main characters are descendants of a human colony, and their dragons are genetically-enhanced creatures who were once just regular old lizards running around Pern with no psychic powers or fire breath. The whole fantasy setup was made possible by science.

8. Kraken, by China Mieville
How can a novel full of ghosts, gods, and Londonomancy be anything but pure fantasy? When the whole point of the novel is that somehow there is a Darwinian natural selection at work on the forces of magic itself - only the most hardy forms of magical belief will survive. Indeed, one of the main forces of good in the story emanates from London's Natural History Museum, where evolutionary theory is somehow embodied in sample jars and preserved animals, coming to life to slay the forces of irrationality and chaos.

9. The Island of Lost Souls
This 1933 movie is a classic example of a fairy tale story that turns out to be based on science (and indeed, it's based on H.G. Wells' scifi novel The Island of Dr. Moreau). Shipwrecked sailors find themselves on a mysterious island where the only inhabitants are people who look like something invented by Ovid - half-animal, half-human, they live in a state of savage grace ruled by a godlike figure. Has a spell been cast upon the island? No. It's just Dr. Moreau, a mad geneticist who has figured out how to splice human and animal together for his own sadistic reasons.

10. Ultraviolet (miniseries)
Like zombies, vampires have been reinvented over the last couple of decades and turned into creatures who exist in the realm of science rather than supernatural fantasy. Nowhere is this more obvious (and awesome) than in the British miniseries Ultraviolet, where vampire hunters use ultraviolet light and chemicals derived from garlic to hunt down creatures who are never called vamps - but who clearly are. The vamps have a scientific agenda, too, and are setting up experiments to figure out what causes their species to be sterile. If you've ever wanted to see a purely scifi vampire tale, this is it.