Visitor Center

The Visitor Center is a section of the penitentiary in Arkham Asylum, which consisted of a visitor room and throne room. During the events of Arkham Asylum, the center served as The Joker's secret main headquarters and base of operations.

Description
Being the only location in Arkham Island that visitors could access, this location was designed for relatives of asylum patients to be able to safely visit patients under close surveillance by the asylum's security.

Visitor Room
The Visitor Center included a room, which included a reception desk for visitors to sign in, as well as multiple booths behind glass in which the asylum patients sat behind when they talked to their relatives. Behind one of the booths was Joker, who posed as a lifeless mannequin and left recorded messages for Batman.

Throne Room
The throne room, which could be accessed via the guard office behind one of the booths of the visitor room, consisted of a large hall, filled with numerous cells for mentally unstable patients and during the Joker's takeover, served as his secret headquarters and had in the far end a huge mountain of gag toys, a top which the Joker had a throne and would record speeches and messages for his men and/or Batman.

Arkham Asylum Incident
After escaping custody and causing havoc in the asylum, the Joker took over the Visitor Center and transformed it into his base of operations and had his men paint a Joker facade on the entrance, all while taking over other important sections of Arkham Island. Anytime after he accessed Arkham West, Batman could enter this building and the Joker, posing as a mannequin with a TV on top of his head, would have a taped recording and do a "psychiatric profile" on Batman, analyzing his "psychosis" and also commenting on Batman interfering with his plans.

After defeating Poison Ivy at the Botanical Gardens, Joker will have fireworks lit up and "invite" Batman over the asylum intercoms to join the party which is at the Visitor Center. Once Batman reaches the front door, which has been vandalized and painted the Joker's face on it, Joker's men will urge and politely invite Batman, who is the guest of honor. Batman can then optionally beat up the convicts and enter the corridor, which leads to the center, and is cheered up by Blackgate Prisoners. Batman can optionally beat up the whole group there as well and then enter the center itself where he is greeted and taunted by the Joker mannequin, which surprises Batman and then reveals itself as the Joker, who had been masquerading as a lifeless mannequin the whole time to evade Batman. Before entering the "throne hall" of the Penitentiary, Joker detonates the bomb-rigged TV, which partially damages the center and briefly knocks out and stuns Batman, who then continues on the Penitentiary itself and finally, the throne room. The Joker awaited Batman atop a throne of gag toys, and vented his frustration on the Ventriloquist's dummy, Scarface. Here, the Joker had massed all his remaining goons and two security guards that he'd injected with the steroid drug, Titan. Having lost their sanity to the chemical, the Titan-powered guards turned on Batman with the Joker's men, although Batman had managed to defeat them all. The Joker then revealed that he had Commissioner Gordon hostage. Trying to fire a Titan dart at Gordon, the Joker was delighted to see Batman take the shot himself. The Joker was willing to take a chance on Titan-because Batman had used up all the antidote on himself. The Titan-powered Joker mutated and took Batman up to the Penitentiary Roof, where he left Batman to fight in an enclosed arena against an army of Blackgate Prisoners. The Joker also strapped Gordon to an electroshock therapy chair, which sent bolts of electricity into him at random intervals. Several news helicopters circled the upper roof, and filmed Batman's desperate battle. Eager to get into their film, the Joker stood on the upper roof, and posed for them. As Joker commented on the news helicopter, Batman pulled him off his perch with his Ultra Batclaw. Batman did this twice, although the Joker had loosed knife-wielding henchmen out to fight Batman and tossed explosive gag wind-up teeth into the arena to kill him in an explosion.

Batman finally yanked the Titan-powered Joker into the Penitentiary Roof for the third time, which causing it to collapse under Joker's weight and knock him into the generator that was used to electrify Gordon's restraint chair. The Joker was finished off as Batman detonated Explosive Gel on his fist while he punched him in the face, and won the fight despite extensive damage to the Penitentiary. An attack force by the GCPD stormed the Visitor's Center, captured the remaining henchmen, and watched over the Titan-powered guards as they returned to normal.

The center, along with the entire asylum, was retaken by the Gotham City Police Department and the rest of the Joker's men were captured and imprisoned.

Arkham City Incident
After the Joker's defeat and the construction of Arkham City, the asylum, along with the center was sold to TYGER and transformed into it's main base of operations.

Arkham Knight Incident
After surrendering to Scarecrow, Batman was captured and taken to a decaying and promptly abandoned Arkham Asylum, which is the Scarecrow's base of operations. After unmasking and injecting him numerous times with Fear Toxin, Batman managed to defeat the Joker's influence inside his mind and defeated Scarecrow.

It is likely that after the events of Arkham Knight, the asylum was renovated once again to accommodate mentally unstable patients and criminals alike, with there being a new warden, possibly the same old orderlies, janitors and doctors that survived the Clown Prince of Crime's carnage, and much better organized and experienced asylum security to ensure that there aren't any future riots. The Visitor Center would likely be renovated as well so that patients may have cells and also speak to their relatives, albeit behind glass for safety and under close security surveillance.

Trivia

 * If Batman kept on visiting the center, Joker's speeches will range from analyzing Batman's motives to stop criminality to references to The Killing Joke.
 * Every time Batman enters the center, he is unable to put on Detective Mode. This was intentionally done to prevent the player from seeing through that the "Joker mannequin" is actually Joker himself.
 * If one were to look at the mannequin, then turn to the right or left for a few seconds and then turn his attention back to the Joker, notice how the "mannequin"'s arms change position each time. This is another hint that the "mannequin" is the Joker in disguise.
 * After beating the main story, the center will be locked and is no longer accessible.