Arkham Asylum was the facility used to hold the criminally insane of Gotham City. The asylum was built over a large under ground cavern and took its water from the river flowing beneth it. The asylum could also house inmates who needed unique environmental needs such as Mr. Freeze who could not survive outside of sub zero tempatures. At least to staff members were driven insane and imprisioned at Arkham. These staff members were Harleen Quinzel who became Harley Quinn and Lyle Bolton who became Lock-Up. On one occasion the asylum was taken over by the inmates and held a trial for Batman. Sometime before the year 2030 the inmates were relocated to a newer facility. After the asylum closed it became the place of Batman and Jokers last confrontation. Joker did not survive the battle. In an alternate reality the asylum was run by a lobotomize Joker. The inmates aswell were lobotomized by Superman and it was protected by Superman robots. Staff Dr. Bartholomew Dr. Joan Leland Dr. Harleen Quinzel (committed) Lyle Bolton (committed) Inmates The Joker Scarecrow Poison Ivy Two - Face Harley Quinn Mad Hatter Killer Croc The Riddler The Ventriloquist Maxie Zuse Lock-Up Mister Freeze Clayface Emile Dorian Baby-Doll