Though he was executed in 1936 for the murder of Grace Budd, serial killer Albert Fish claimed he killed 100 victims and "had children in every state."

Despite mountains of evidence, the mystery of what happened to Roland T. Owen in Room 1046 of the Hotel President in Kansas City remains unsolved to this day.

On March 31, 1922, a mysterious killer murdered a German family of five — Andreas and Cäzilia Gruber, their daughter Viktoria Gabriel, Viktoria's children Cäzilia and Josef — and the family's maid Maria Baumgartner. To this day, the killer has never been identified.

Reported to have lived 122 years and 164 days, Jeanne Calment was allegedly the longest-living human of all time — despite heavy consumption of chocolate, cigarettes, and red wine.

Between 1978 and 1990, Andrei Chikatilo murdered at least 53 people and mutilated their bodies — all while slipping right through the authorities' fingers on multiple occasions.

In April 2014, two Dutch tourists named Kris Kremers and Lisanne Froon went hiking in Panama and never returned. Months later, officials found their bleached bones and disturbing pictures.

A serial killer who murdered four girls in late 1980s Japan, Tsutomu Miyazaki was known as the "Otaku Killer" for his obsession with anime and pornography.

From Elisa Lam to Richard Ramirez, the Cecil Hotel's history has been filled with bizarre horrors since it was built in 1924.

On January 15, 1947, 22-year-old aspiring actress Elizabeth Short was found brutally murdered in Los Angeles — with her body cut in half and a ghastly smile carved into her face.

A successful painter who lived in Paris, Einar Wegener would undergo groundbreaking gender-affirming surgeries and live as Lili Elbe before dying in 1931.

Karla Homolka helped her husband Paul Bernardo rape and murder at least three victims between 1990 and 1992 — but she walks free today after serving just 12 years.