the Gathering
"Redlitch: You think of witches meeting on a blasted heath, don't you?Shep: I don't think I think of their meeting at all.
Gillian: Where do they meet? Do you know?
Redlitch: Sure, I know. One of their main places is up in Harlem. It's an old vaudeville house. There's another down in the Village. And sometimes they have them in a suite of offices on the top of the Woolworth Building. You'd be amazed what's going on under your nose that you'd never suspect. Talk about spy-rings and organized vice - they're nothing compared to it."
~ Bell, Book and Candle
The world you see isn't the real world, or at least not all of the real world. There's a whole other world just behind you, and if you turn quickly enough you might catch a glimpse of it. It happens more often than people think, that's why they've gotten so good at ignoring it. But it's there, all the same, and if you're in the right place at the right time, it might just notice you, too.

