Nurmengard Castle

Gellert Grindelwald was imprisoned in the top-most cell in the highest tower inside Nurmengard after his defeat by Dumbledore. His followers were called The Alliance. The alliance was an association of seditious witches and wizards who followed the Dark wizard Gellert Grindelwald in the early 20th century. Fanatics dedicated to Grindelwald's ideology of wizarding supremacy referred to themselves as his "acolytes".

Nurmengard Castle was located somewhere in the Austrian Alps, and functioned as a wizarding prison. Originally built by Gellert Grindelwald to hold his opponents, it also served as the base of operations for Grindelwald and his followers. Ultimately, it was used to imprison Grindelwald himself after his defeat by Albus Dumbledore in 1945, until his death in 1998.

Nurmengard was a stone fortress at the edge of a mountain. It had a tower with a cone-shaped top, possibly being a watch-tower. There was a building connected to the tower, that was slim with windows. Nurmengard also had a courtyard, which was gated. Whenever there was an outsider, one or more of Grindelwald's acolytes would interrogate them, while wanded. On either side of the courtyard were prisons with black-coloured bars, very probably enchanted by Grindelwald to hold less powerful enemies, while the other ones were held captive further inside, in the castle's interior. On top of these prisons were houses. On the mountainside, at the back of Nurmengard Castle, were a series of steps that led to a hill, where Aurelius Dumbledore would wait for his phoenix to arrive.

This tower was a square shaped tower with a cone shaped top. Inside the main building, there was a hallway with velvet carpet detailed with white lines and also a table. When Grindelwald revived the dead Qilin he had recently killed, Grindelwald went to a room with two pools of water, and placed it in one of the pools of water somewhere in the castle. This pool was possibly on the lowest floor of the castle, possibly even underground, as there were only upward-leading stairs there. Written on the walls of the room where these pools was located were rune symbols, including a fancy-looking number 3. There were also several candelabras in the room, some of which were on the ground, while some were chained to the ceiling.

Aurelius Dumbledore washed his hands in this room while talking to Queenie Goldstein. There was also a mirror that Aurelius used to send messages to Aberforth's mirror in Hog's Head Inn. Aurelius's use of the mirror was unknown to Grindelwald and the rest of the Alliance. Connected to the hallway was a room with large wooden doors. Inside the room held tables, chairs, a desk, cabinets with books, a gold chandelier, a stove and more things. The walls were coloured red and yellow with a pattern. They also had six different heraldic symbols on the walls. At the end of the room was a big window, with a staircase going down into a lower part with a table, chair and a table. Up the staircase, was a narrow staircase, leading into the tower. Half a decade later, Nurmengard turned into a gigantic, towering building made of black rock and with high walls, that is described as "jet-black", "forbidding", and a "grim fortress". The cell that was inhabited by Gellert Grindelwald since 1945 had been a dark and ominous room in the highest tower, with a hard bed and a ragged, thin blanket.

The prison was built on the orders of the Dark wizard Gellert Grindelwald in order to hold his opponents. Grindelwald's slogan "For the Greater Good" was carved over the prison's entrance.

By 1926, the castle also served as the headquarters for Grindelwald and his Alliance during the Global Wizarding War. Later in 1927, Gellert gave Aurelius Dumbledore a spare wand and bestowed him alleged information about who he might be and what Albus Dumbledore is up to.

In 1932, Aurelius and the other acolytes brought to Nurmengard a Qilin kidnapped from China. Soon, the election for the Supreme Mugwump of the International Confederation of Wizards there were to be held, which Grindelwald wanted to win. When the Qilin did not bow to him, Grindelwald cut its throat with a knife, and moments later in the creature's blood he saw visions of Albus Dumbledore with the blood pact pendant and Newt and Theseus Scamander heading to Hogsmeade.

Later, Grindelwald had visions of Yusuf Kama heading to Nurmengard and Dumbledore in the Hog's Head Inn. When Vinda Rosier appeared, Grindelwald told her that they should prepare to leave the castle the next night, because they would have a visitor in the morning. As Aurelius's phoenix flew over him, Rosier asked Grindelwald if Aurelius could really kill Dumbledore. Grindelwald stated that the phoenix was supposed to protect Aurelius in connection with his assigned task, and Aurelius's pain was the only way he could defeat Dumbledore.

Soon Grindelwald was visited by Yusuf, who told him that he was sent by Dumbledore to spy on him, and asked Grindelwald what report he was to pass on to Albus of this visit. Grindelwald ordered Queenie to use Legilimency on Kama. Queenie read that Kama was furious at Grindelwald, after the Dark wizard killed Leta Lestrange, his sister. Grindelwald erased with the Elder Wand the painful memory of his sister's death, altering his memories.

Soon after, a gathering of Grindelwald's followers took place in Nurmengard, where the Dark wizard gave his speech. After that, he reanimated the dead Qilin in the underground pools in order to use it during the election for Supreme Mugwump. In the water Grindelwald had a vision of the second Qilin and became enraged at Aurelius, ordering him to find the second Qilin.

After a number of years of terrorizing Europe, Grindelwald was confronted and defeated in a duel between him and his former best friend and lover Albus Dumbledore on the dawn of 2 November 1945.

Grindelwald was imprisoned in the top-most cell in the highest tower inside Nurmengard after his defeat by Dumbledore. His cell had a small window, too narrow for a man to leave or enter, a hard bed and a thin blanket. It is unknown if there were any other prisoners ever held at Nurmengard, but around the time of Grindelwald's death, it is likely that he was the only prisoner present as the past inmates were likely incarcerated there at Grindelwald's behest. Grindelwald was certainly fed and kept alive for fifty-three years, so there was at least a supply of food and someone (or something) bringing it to him, although he was emaciated, frail and missing teeth.

In his quest for the Elder Wand, Lord Voldemort travelled to Nurmengard in 1998, using his skills of unsupported flight to break into Grindelwald's cell. After confronting him for information on the Elder Wand's location, Voldemort killed Grindelwald and then flew away.