Walburga Black is a painting by Antun Aron: Portrait of an Old Woman (1887). Grimmauld is Strahov Monastery Library and St. Vitus cathedral in Czechoslovakia. Mornington Crescent is a street in Camden, London. You don’t have to go to Grimmauld Place to browse through the Herbarium Blackwellianum . We borrowed The Necrotelecomnicon