This is a novel I'm working on and is mainly in the planning stages, though I've also somehow written quite a bit (but I can't use much of it since the plot keeps changing on me). Half of the setting takes place in a city that is half medieval, half sci-fi. The other half takes place on modern day earth. Basically, there are several cities floating around in space. These cities are high tech, but also rely heavily on magic. Certain parts of their views are very ancient, and they have large castles and old looking buildings. But it's the cities themselves and how they function I'm actually wondering about. They look like round balls when seeing them from afar, and they are surrounded by a sphere that gives them heat, night and day, oxygen, gravity, etc. If they fall out of the sphere, they're dead. The sphere's “engine” keeps them from floating upwards, but not from falling down. The city the story takes place in has a population of roughly ten thousand. The city is built in a circle, with the castle on top, and the “engine” on the bottom. All the houses, parks and public buildings are connected by diamond stairs with gold railings (half for safety, half to show off their wealth to the other floating ball cities). Not sure if all that is understandable. This is pretty much how I'm going to explain it, though I'll be more detailed when it comes to how the city actually looks. But would you want more of an explanation of how it works? I'm kind of just going: “it's magic and science combined. It's über-powerful and ever-working, so no point in explaining it more than that.” I don't even know how it works to be honest. The engine does everything I need it to. The ultimate deus ex machina.