Living in my own little world

Building a world for one’s characters to inhabit is easy, initially. It all starts by saying What if? What if North Korea were to set off a nuclear device in downtown Los Angeles? What if there were ancient, angry gods buried in West Texas and Greenland? What if Omaha was actually an interesting town?

But then comes the hard part — you have to make sure the world you’ve just created makes sense, obeys some sort of in-world logic. Even if it’s apparent only to you, you have to know every little thing going on in that world, and know what makes it fundamentally different to the real world you live in every day. A lot of times, this just means checking and checking again, making sure you didn’t break any of your own rules (or if you did, you can justify doing it). Sometimes, though, it means putting up a dry-erase board and covering it with notes and scrawlings like a madman.

So who do you think does a really good job of worldbuilding? What stories have you seen where it made a good effort, but ended up failing in the end?