First Appeared: Neverwhere (Episode 1, "Door," September 12, 1996)
Founding Father: Neil Gaiman and Lenny Henry
Notable Residents: Door, the Marquis de Carabas

This British television series from the early '90s (or, even better, its subsequent novelization) works on a brilliant concept, which finds Gaiman imagining London Below. People in London Above don't see people from their subterranean counterpart and vice versa. And what's even more interesting, London Below shares many of the landmarks, only with a more fantastic and plauful bent. Knightsbridge is an actual bridge swarmed in darkness from the souls swallowed therein. There are floating markets, trains without schedules, rat people, and a bridge leading to an angel located within the British museum. London Below is an expansive tribute to London, while injecting it with a new vitality and purpose.