I contributed a guest editorial about building a fantastical city to Matrix a couple of months ago. It's now available online, and since the link looks temporary, I'm also reproducing it below.
One night in 1993, I woke up with a vision in my head of a woman in a window and a missionary looking up at her from a crowded street. Every detail had a kind of super-heated intensity to it. As if in a trance, I went to the computer and typed up about six pages about the characters and the city. The name of the city came to me just as I was about to type it for the first time: Ambergris. And, suddenly, as if the name was a key opening a locked door, I found an entire fantastical city in my head. The only problem was finding the time to get it all down on paper. So, over a period of nine years I wrote an entire book of stories about Ambergris, eventually published as City of Saints & Madmen. I also wrote the beginning of three novels, one of which has finally been completed and will be published as Shriek: An Afterword next year.
Although Ambergris came to me in the equivalent of a vision or waking dream, and even though I had many details about the city in my head from that moment forward, writing about Ambergris wasn't like channeling spirits after that initial inspiration. No, instead, I had to learn a lot about how to create a believable and yet imaginative setting.
Readers make assumptions about the real world that they do not make about fantastical worlds. A reader doesn't automatically buy into Ambergris in the same way that the same reader would believe a story set in my hometown of Tallahassee, Florida. Fantasy writers have to take greater care with their settings as a result, while not letting setting overwhelm the rest of the story.
Why do we read and love China Miéville's New Crobuzon novels? Why does the work of Mary Gentle or Michael Moorcock excite us? It's the quality of the imagination applied to setting and character. How you get there can be a long, hard slog because world building (which includes creating interesting characters) requires a tremendous amount of work and research. You can't just throw different elements together without making sure they work in combination. Otherwise, the reader will throw the book across the room. Readers will, rightly, revolt if you don't give them some sort of anchor, whether a consistent architectural description or consistency in types of clothing. (Noting that there are also many implausible juxtapositions in our real world--countries where people have cell phones but drive cars from the 1950s, for example.)
At the same time, the world has to be metaphorically and metaphysically interesting, which means you can’t be too consistent. Everything can’t be tidy and pat, and it should be in flux—it should be, in a way, alive. Above all else, to be interesting, a fantastical city should be a reflection of the writer’s obsessions and subconscious impulses. (M. John Harrison’s Viriconium stories are a good example of this trait—Viriconium is always shifting, always different.)
What's interesting is that readers of City of Saints & Madmen will often tell me "I love that part you made up about such-and-such," and I'll have to tell them I didn't make it up at all—it came from Byzantine or Venetian history. Others are sure that something I made up actually has a basis in historical fact. All this means is that the real world is a very bizarre, strange place and that fantastical fiction is perhaps best suited to comment on this fact. Anyone who takes the time to create echoes of the real world in their fantasy worlds will eventually reach this realization.
I love fantasy because the world is a place of great beauty and horror, and fantasy is the only way I can fully express what I know about this contradiction. Fantasy, and world-building, then, is not escapist for me--or, I imagine, for other world creators. Instead, it's about realistic people. It's about the fact that this place we live in is full of unexpected marvels and things that are strange and alien even if we don't always realize it.