Durmstrang is known for placing an emphasis on the study of the Dark Arts. While other schools of magic in the series limit the study to "Defence Against the Dark Arts", Durmstrang students actually learn them. In "Deathly Hallows", it is revealed that the Dark wizard Gellert Grindelwald attended Durmstrang. He also carved the symbol of the Deathly Hallows onto the school's stone walls. Although Durmstrang teaches the Dark Arts as part of its curriculum, apparently the experiments performed by Grindelwald were considered too extreme even by the school's standards as he was expelled because of them.