Warning: Graphic and disturbing content ahead including mentions of sexual assault, abuse, and murder.
1. Nannie Doss, aka "Giggling Granny" and the "Lonely Hearts Killer," who was responsible for the deaths of at least a dozen people between the 1920s and 1950s, including four husbands, two children, and other family members.
2. Miyuki Ishikawa, aka the "Demon Midwife", who was charged with murdering many infants (possibly even over 100) through purposeful neglect. Her crimes were committed with accomplices during the 1940s in post-World War II Japan.
3. Aileen Wuornos, aka "The Damsel of Death," a serial killer who murdered and robbed six men (and possibly a seventh) while doing sex work in Florida from 1989–1990.
4. Belle Gunness, a Norwegian American serial killer active in Illinois and Indiana from 1884–1908, suspected of killing up to 15 men for insurance. Her children died in a house fire in 1908 and it's unclear if the body of a woman found with them was Belle.
5. Sara María Aldrete, aka "La Madrina," a convicted serial killer who also ran a drug-smuggling and human sacrifice cult with a man named Adolfo Constanzo in Mexico during the '80s.
6. Amy Archer-Gilligan, a serial killer who also ran a nursing home, murdered at least five people by poisoning them in Windsor, Connecticut during the early 1900s.
7. Kristen Gilbert, a former nurse who worked at the Veterans Affairs Medical Center in Northhampton, Massachusetts in the late '80s. She was convicted of four murders and two attempted murders of patients.
8. Stacey Castor, a convicted murderer from Weedsport, New York who killed her husband with antifreeze, attempted to kill her daughter with crushed pills mixed into a drink and was also suspected of killing her first husband in the 2000s.
9. Dorothea Puente, who ran a boarding house in Sacramento, California where she killed various elderly people and people with mental disabilities in the '80s. The total victim count reached nine confirmed murders and six unconfirmed.
10. Marybeth Tinning, whose nine children died suspiciously under her care in New York during the 1970s. It is believed she poisoned them over a span of several years. Before being caught, she managed to convince people her children had died of different things like acute meningitis, seizures, cardiac arrest, sudden infant death syndrome, acute pulmonary edema, and bronchial pneumonia.
11. Elizabeth Báthory, a Hungarian countess who is believed to have tortured and killed hundreds of young women in the 16th and 17th centuries. The lore is that the countess thought bathing in her victims' virginal blood would give her eternal youth.
12. Myra Hindley who was called "the most evil woman in Britain" in the press for her involvement in killing five children with her partner Ian Brady in the 1960s.
13. Karla Homolka, a serial killer who acted as an accomplice with her husband Paul Bernardo (also a serial killer) in the rapes and murders of at least three teenagers, including her own sister from 1990–1992.
14. Tillie Klimek, who claimed to have "precognitive dreams" predicting her victims' deaths. She is believed to have poisoned and killed three husbands as well as neighborhood children in Chicago during the 1920s along with an accomplice.
15. Frances Knorr, aka the "Baby Farming Murderess," an English woman who moved to Australia, became a baby farmer, and is believed to have killed, by strangulation, multiple children in the late 1800s.
16. Linda Hazzard, aka "The Starvation Doctor," who was responsible for at least 15 deaths in the state of Washington in the early 1900s.
17. Rosemary West, a serial killer in England who murdered, sexually assaulted, and tortured at least nine women (possibly more) along with her husband, Fred, from 1973–1987.
18. Beverley Allitt aka "The Angel of Death," who was convicted of killing four children, attempting to murder three more, and causing grievous bodily harm to six others at a hospital in Lincolnshire, England between February and April of 1991.
19. Amelia Dyer, a baby farmer turned serial killer in England who adopted and then murdered many children over a 30-year period in the late 1800s.
20. Blanche Taylor Moore, a suspected serial killer who was convicted of poisoning her boyfriend and was also believed to be responsible for the death of her first husband, father, and mother-in-law.
21. Finally, Joanne Dennehy who committed a series of murders in Cambridgeshire, England in March 2013. All three of her victims were male and she had killed them by stabbing.
