13. H. H. Holmes
Known as ‘Dr. Henry Howard Holmes,’ this guy built a hotel specifically as a playhouse for him to murder people in. He is suspected of murdering up to 200 people. The murder hotel contained, “a maze of over 100 windowless rooms with doorways opening to brick walls, oddly-angled hallways, stairways to nowhere, doors openable only from the outside, and a host of other strange and labyrinthine constructions.” There was also a “corpse chute” that allowed Holmes to drop bodies from the hotel into the basement.
Elizabeth is maybe the most prolific female serial killer ever, and is known as the “Blood Countess.” She tortured and murdered up to hundreds of young girls in her castle with the help of her servants.