Arkham Asylum has become one of the most iconic locations in all of comics. It houses some of the greatest villains DC has ever seen. These include the likes of Joker, Penguin, Bane, Harley Quinn, Mr. Freeze, and so many more.

Over the years Batman has had many interactions with the famed institution. He has time and time again locked up his foes there. There have even been a few occasions were the inmates took control and he had to fight them all off and put them back in their cells.

RELATED: Batman: 10 Scariest Things Scarecrow Has Ever Done

While many comic fans know about Arkham's history locking up super-criminals, many fans don't know the many secrets this asylum holds. Here are ten of Arkham's greatest secrets, revealed.

10 10. The Death of Ingrid Karlsson & the Birth of Astrid

Jeremiah Arkham, the son of Arkham Asylum's founder Amadeus, had a daughter with a fellow Arkham doctor. The mother, Ingrid Karlsson, was one of the most liked and respected doctors in all of Arkham. Even the Joker respected her.

While Ingrid was pregnant with Astrid, a riot broke out at Arkham. The sudden stress of the situation forced Ingrid into labor. Hoping to protect the one doctor they actually respected, villains such as Solomon Grundy, Clayface, Joker, and Harley Quinn did their best to defend her. The baby, Astrid, was successfully delivered but unfortunately, Ingrid was killed.

9 9. The Arkham Knight

Homeschooled within Arkham's walls, Astrid Arkham made friends with all of the inmates of the asylum. Due to their twisted nurturing, Astrid grew to hate Batman. To her, he was simply the demon who continued to hurt her friends. Eventually, Astrid even grew to believe that Batman was the one who killed her mother.

Seeking revenge on the caped crusader, Astrid spent her life training to become a fierce warrior. Eventually, she took on the mantle of the Arkham Knight and began her own crusade against the Dark Knight.

8 8. The Fall of Amadeus Arkham

Originally the founder of the asylum, Amadeus Arkham eventually became one of its most insane patients. Originally, Arkham's goals were pure. He wanted to help the mentally insane, much like his mother. As time passed, he became more and more abusive with his patients and was driven further and further into insanity.

Arkham later tried to kill his stockbroker and was then locked up in a cell. He scratched insane ramblings all over the walls with his fingernails and continued to sing "The Star-Spangled  Banner" until he died.

7 7. Methods of Treatment

Unbeknownst to the public at large, there are many shady practices going on behind the asylum's doors. Even if the public did know, there are probably few who would disapprove. The inmates are, after all, some of the vilest villains to ever walk the streets of Gotham.

One such example of the type of horrible treatment was shown in Arkham Asylum: A Serious House on Serious Earth. Toward the beginning of the story, Batman learns that Two-Face has been immobilized by his new therapy. Taking away his coin, the doctor replaced it with a die, and then a tarot deck. Left with too many options, Two-Face is unable to even make small everyday decisions leaving him immobilized.

6 6. Terry Gene Kase

Ra's al Ghul is one of Batman's most connected enemies. Due to his leadership of the League of Assassins, there is no prison he could not be broken out of. In order to make sure he never escapes again, Batman comes up with a clever plan to lock Ra's up in Arkham Asylum.

RELATED: Batman: The 10 Most Mysterious Things About Ra's Al Ghul & His Family

Falsifying photos, medical records, police reports, and the like, Batman places Ra's in Arkham under the pseudonym Terry Gene Kase. Although he eventually escapes, this was one of Batman's most clever attempts to sequester Ra's, and no one at Arkham had any idea who Terry really was.

5 5. Hugo Strange

HUGO STRANGE

One of the psychiatrists at Arkham, Hugo Strange turned out to be one of the most nefarious villains Batman has ever faced. For a time, Strange was even the Chief Psychiatrist at Arkham.

Strange is not only one of the most sadistic Batman villains, but he is also one of the most brilliant. Strange was even able to deduce the true identity of Batman using only his wit. Such a dangerous foe was hidden for so long within the walls of Arkham, pretending to simply be another member of the staff.

4 4. The Last Arkham

During "The Last Arkham" storyline, Batman himself was locked within Arkham. This was all a ploy, as Batman suspected the inmate Victor Zsasz had found a way to escape. He needed to infiltrate the hospital to investigate further.

It was not only revealed that Zsasz had secret passages built within Arkham years before, but this story also showed that Jeremiah Arkham was following in the mad footsteps of his father. Slowly but surely, it seemed that Jeremiah was starting to lose his mind and become more and more abusive with his patients.

3 3. The Mad Dog Murders

Prior to the opening of Arkham Asylum, Amadeus Arkham worked at a psychiatric facility in Metropolis. While there, he was called in to consult on the case of Martin "Mad Dog" Hawkins.

After his return to Gotham, Amadeus received a call from the police that Hawkins had escaped. Upon returning home, Amadeus found his wife and child had been raped and murdered by the sadistic psychopath.

2 2. Amadeus' Revenge

Arkham-Asylum-in-Gotham-show

After opening the asylum, Amadeus remained the head of the hospital despite his deteriorating mental state. One of his first patients, by request, was Mad Dog himself.

Amadeus "treated" the murderous criminal for months. Then one night, Arkham tied Mad Dog up to an electroshock couch and shocked the criminal to death. While the other doctors helped cover up this death as an "accident," they all knew too well that Amadeus had enacted his revenge.

1 1. The Truth of Elizabeth Arkham's Death

Amadeus Arkham founded this institution because of his mother. Elizabeth Arkham suffered from severe mental illness for the majority of her life, up until her suicide. This tragedy sparked Amadeus into action. Except it wasn't a suicide at all.

It turns out that Amadeus had actually killed his own mother, and later repressed the memory. Amadeus Arkham had been insane all along.

NEXT: 5 Alternate Origins Of Batman That Are Better Than The Original (& 5 That Are Worse)