In Batman: Arkham Asylum, blowing up a wall in the Warden's Office reveals a secret room that shows blueprints for "Gotham City" - hinting at the game's sequel, Arkham City. : r/GamingDetails
Arkham Asylum Secret Room Reveals City Blueprints | TheSixthAxis
Warden's Secret Room Easter Egg! Batman Return To Arkham Asylum Part - 11 🎃 - YouTube
Steam Community :: Guide :: The wardens secret room
Remember this secret room in Batman Arkham Asylum? - YouTube