Despite being the platonic ideal of a big budget, blockbuster video games, the Call of Duty series has had its fair share of glitches, and the first Modern Warfare was no exception. Many of them included ways to escape multiplayer maps entirely, falling out of the levels into strange and bizarre mirror universes bereft of textures and other people.
Reddit user DaJeroen discovered a friendly nod to the game breaking bugs of yester-year in the form of a "caution" sign over one such location, reminding players who pass by to mind the wet rooftop in case they should accidentally slip and fall into another dimension.
While Modern Warfare's underworlds weren't nearly as creepy or haunting as some others, like Dragon Age: Inquisition's, they had their own desolate charm; a meditative reprieve from all the shooting and trash talk.
Modern Warfare Remasterd does have a few tricks up its sleeve, including a number of cheats that range from exploding fruit to replacing every enemy with Victor Zakaev. It's also looks like there are still a few inter-dimensional portals lying around.