Arkham Asylum (Earth-1)

Arkham Asylum is a prison in Gotham City, for the legally insane.

History
For years, Arkham has been used to incarcerate notorious villains of Gotham, who were defeated by Batman and Robin.

Breaking Out Of Arkham
Inmates Harley Quinn, Mister Freeze and Firefly launched a breakout of the prison, by first unleashing Killer Croc from his cell. From there, multiple other villains joined in the breakout, such as the Riddler, Scarecrow, Two-Face, Poison Ivy and Kite Man.

Inmates

 * Bane (status unknown)
 * Firefly / Garfield Lynns (formerly)
 * Harley Quinn / Harleen Quinzel (formerly)
 * Killer Croc / Waylon Jones (formerly)
 * Kite Man / Charles Brown (formerly)
 * Mister Freeze / Victor Fries (formerly)
 * Poison Ivy / Pamela Isley (formerly)
 * Riddler / Edward Nygma (formerly)
 * Scarecrow / Jonathan Crane (formerly)
 * Two-Face / Harvey Dent (formerly)

Related

 * Appearances of Arkham Asylum
 * Mentions of Arkham Asylum