Bluebeard and his wife by Gustave Doré
is a folk tale about a wealthy man who marries a great beauty. He gives his wife a bunch of keys that open all the rooms in his castle, warning her not to open the door to one small room, although she is free to explore everywhere else. Inevitably she heads for the forbidden chamber and discovers the bodies of Bluebeard's previous wives, all of which he has murdered. Bluebeard is angry with her for having opened this chamber and threatens to kill her; however her brothers arrive in the nick of time and kill him instead.
The Bluebeard story has been reinterpreted by a number of artists, including the Hungarian musician Bela Bartok, who wrote an opera called Bluebeard's Castle (listen to this on Spotify).