Obviously, since the player can't go beyond the walls of the prison area, you'd assume the developers just threw up some pictures of the skyline and called it a day. But no, they went through the trouble of creating an entire ghost city out there that you can't even touch. The only way to access it -- which 99 percent of gamers won't be aware of, never mind bother with -- is to use an obscure glitch to send yourself flying up out of the game world, at which point you can soar through the air like some kind of small, airborne mammal. A flying squirrel, maybe?
Once you've slipped off the surly bonds of your PlayStation, you're free to explore Gotham to your heart's content. Despite this being a part of the game that you were never intended to see, the city is surprisingly detailed. You can even dive-bomb cars driving around the city.
Reminder: the regular game features zero cars driving around the city.