Arkham Asylum is Gotham City's psychiatric hospital. Many of it's patients are from Batman's rogues gallery including, but not limited to The Joker, the Penguin, Poison Ivy, The Riddler, Bane, Killer Croc, Harley Quinn, Clayface, etc.
By the maze, first you need to press a button at the left side of the entrance that will open a door. Go through the traps to the ElementalKeystone and activate it. A door will open at the beginning of the maze, leading to the fire section, and you must cross it and press the button, which will open the gates, leading to the plant section of the maze. Once you cross the section, press the final button and cross the electrified corridor where the Gold Brick is.
