The Harry Potter films initially started off in a lighthearted manner, even when a giant snake is prowling the school grounds or a dark lord is actually attached to your teacher's head. With the advent of Prison of Azkaban, however, things got a lot darker. We all found out that there was actually a prison for bad wizards and witches with equally horrific prison guards.
What makes Azkaban more interesting is that the Dementor guards are more like tigers who take a bite out of the prisoners whenever they're hungry. Still, how Azkaban operates or came to be was quite confusing for those who skipped the books. Thankfully, there's a wealth of knowledge about Azkaban left out by the movies. Here are the grisliest facts about Azkaban which the Harry Potter films left out:
In the film adaptation, particularly in Harry Potter and the Order of the Phoenix, Azkaban was a triangular tower. However, the books never really went into Azkaban's structural appearance, only that it was a fortress. The triangular shape was just the imagination of the filmmakers since Harry never really saw Azkaban and could not describe its appearance in the books.
Other artist's depictions of Azkaban appear to be a regular tall prison tower with four outer walls instead of three. That isn't to say that the Azkaban in the films was not imposing. In fact, it appeared more so because of the odd architecture.
You might be wondering why Azkaban's brimming with Dementors, right? Well, that's because originally, Azkaban was a fortress built by the sorcerer Ekrizdis, who himself was a powerful and insane practitioner of the Dark Arts. Ekrizdis actually lured, tortured, and killed Muggle sailors there up until he died and the concealment charms faded. This made Azkaban visible to the Wizarding World.
Once they discovered the evil place, it was already infested with Dementors because of what took place there. The Dementors had already grown powerful in Azkaban. Hence, the Wizarding World was afraid that they might infest somewhere else if Azkaban was destroyed. So, they just left the place alone. Azkaban became a prison only until a sadistic Minister of Magic, Damocles Rowles, suggested using it after the Wizarding World went underground. The place did seem like a perfect dumping place for evil wizards and witches since it already had innate "guards" and was concealed from Muggles. However...
Dementors never left Azkaban because through there, they had an unlimited supply of "food." Prisoners' remaining hopes, dreams, and happiness got sucked out by the guards of Azkaban. Additionally, the foul Dementors are kept out of sight and trouble. It's a happy arrangement... unless you're a prisoner.
Because of the constant feeding of the Dementors on the prisoners, they are left only with despair. They are gradually reduced to a soulless shell of their former selves, knowing only evil and pain. As a result, most of the prisoners in Azkaban go insane, even the ones with light sentences.
Once the Dementors are finally done reducing the worst offenders of Azkaban to living corpses, there's no going back for the prisoners. They usually die, either of old age or if they're lucky, death by despair. Thus, the Dementors will have no use for them this way, and those cells will not empty themselves.
That is where Azkaban's own graveyard finds its function. It's actually the Dementors themselves who empty the cells of corpses and bury them in Azkaban's graveyard. Relatives of the dead prisoner are then free to visit the graves.
According to J.K. Rowling, the name Azkaban was an amalgamation of two concepts and names. The first one is Alcatraz, which, like Azkaban, is a prison island and is one of the harshest prisons on Earth. It also just so happens that Azkaban is also located in the middle of the sea and was inescapable for nearly three centuries in the Wizarding World. In a sense, Alcatraz is the Muggle equivalent of Azkaban.
The second notion is the Hebrew word "Abbadon" which literally translates to a "place of destruction" or the "depths of hell." Azkaban's name was inspired by both ideas. Lovely.
One would think that such an awful place would incite conflict among Wizarding World authorities, after all, even Albus Dumbledore was opposed to it. Rowles' successor as a Minister of Magic, Eldritch Diggory, actually visited the prison and what he saw there demoralized him so much that he immediately proposed an alternative to the inhumane Azkaban.
Sadly, Diggory died of a disease before such a decision regarding Azkaban's replacement was reached. Since then, no Minister until Voldemort's final defeat had opposed the idea and operation of Azkaban, mainly because no one has ever escaped.
Another scary thing about Azkaban is that it probably did not even need walls. The Dementors were enough to keep the prisoners weak, deranged, or incapacitated to cast magic, much less apparate out of there. Despite that, Azkaban most likely has an Anti-Apparition jinx in order to prevent wizards and witches apparating in or out of the prison.
There is also the fact that only the most authoritative of wizards or witches can visit Azkaban at will. Even so, it's not exactly a place one would visit to see their incarcerated relative or friend.
While it is true that Azkaban's 300-year clean streak was broken, it was not Sirius Black who first managed the impossible deed of escaping the hellish prison. That deed goes to... Bartemius (Barty) Crouch... Junior!
It can be recalled that Crouch Jr. was actually imprisoned by his own father, Crouch Sr. after the latter discovered that he was a Death Eater. He did spend some time in Azkaban. Still, it seems his own father and mother could not endure him being in the prison. So, Crouch Jr.'s dying mother drank polyjuice potion to transfigure into his appearance, helping him escape Azkaban in the process. Crouch Sr. was also instrumental in this escape as he was one of the few authorities with enough power for a special visit at Azkaban.
Dolores Umbridge was probably more hated than Voldemort and rightfully so. You'll hate her even more after the fact that she actually sent Muggle-borns to Azkaban merely for their heritage under the pretense of them "stealing magic." She has actually done this to quite a lot of Muggle-born witches and wizards ever since she got reinstated as the Under-Secretary in the Ministry of Magic after Voldemort took over.
Some Muggle-borns were lucky enough to get released before the Dementors could damage them enough. However, some also did not survive the dreadful conditions of Azkaban and died, all because of Umbridge.
If there ever was a person who deserved to be in Azkaban more than anyone, it would certainly be Dolores Umbridge. Thankfully, J.K. Rowling did reveal that she got sent there after Kingsley Shacklebolt took over the Ministry of Magic. There, Dolores got her just desserts and was sentenced to life imprisonment for her crimes against Muggle-borns.
The sad part about that, however, is she did not experience being tortured by Dementors. Ever since Kingsley Shacklebolt took over, the guards of Azkaban were replaced with Aurors, giving it a less grim atmosphere. At the very least, Umbridge got what she deserved.