Aptly nicknamed the Blood Countess, #ElizabethBathory was a Hungarian noblewoman, and she was probably the most prolific female serial killer of all time. At the end of the 16th century and beginning of the 17th century, Bathory tortured and killed up to 650 girls and young women at her castle in Cachtice, modern Slovakia. The macabre nickname came from her apparent tendency to bathe in the blood of her victims as she believed it would help her maintain her youthful-looking skin. #orphan