A city filled with the wrong graphics, the wrong collision detection, glitchy (surprise) visual stability and floor that often isn't the floor, actually acting like water instead. Obviously it's completely broken and was never intended to be a place you could visit during normal play. But you can!
How to get it: The trick is to get out of the Safari zone while its step limiter is working. Get into the Safari zone, try to leave but then say you want to stay. Then save your game, reload it, exit the zone, tell the guy at the desk you don't want to play, then head to Cinnabar Island (or some others) and surf until your steps are up. Boom! Glitch City.