Like Hogwarts, Durmstrang is located inside a castle. The castle is only four stories tall and fires are only lit for magical purposes. It has very extensive grounds. Durmstrang has a reputation for teaching the Dark Arts, which is due to its headmaster, Igor Karkaroff. Karkoroff was a Death Eater, but he got out of Azkaban by giving the Ministry of Magic dozens of names of his co-conspirators. Since then he's taught the Dark Arts to virtually every student who stepped into his school. He does not admit Muggle-borns to his school.
Bulgarian Quidditch Seeker, Viktor Krum, attended Durmstrang, and was still in school during the 1994 World Cup. In the 1994 Triwizard Tournament, Durmstrang's champion was, to nobody's surprise, Viktor Krum. It was ironic that Krum attended the Yule Ball with Hermione, who is Muggle-born and wouldn't have been admitted at his school(Karkaroff wasn't pleased with Krum's choice, but didn't say anything.)
After the events of Harry Potter and the Goblet of Fire, Karkaroff fled after Voldemort rose again. It is not known who took over, or whether the school lost its bad repuation due to this.
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