In the early 1970s, the Alphabet Murderer stalked Rochester, New York, killing girls who had the same first and last initial – and these horrific crimes remain unsolved to this day.

The "Mad Gasser of Mattoon" allegedly attacked more than two dozen Illinois townspeople in 1944, but many now believe this disturbing episode was actually a case of mass hysteria.

Li Ching-Yuen was reportedly 256 years old when he died in 1933, though genetics experts say that's "impossible."

The founder of Gangster Disciples, Chicago gang leader "King Larry" Hoover only grew his empire after he was sentenced to prison in 1973.

From the Chapel of Bones to the Empire of the Dead, explore some of the spookiest catacombs on Earth with these eerie images.

Despite being one of the richest countries in the world, England was also home to some of the most destitute neighborhoods, with 35 percent of Londoners living in poverty at the end of the 19th century.

In the late 1800s and early 1900s, explorations into the jungles of South and Central America uncovered ancient ruins hidden under vegetation — revealing the rich history of the people who once lived there.

From 1917 to 1925, Dr. Harold Gillies performed more than 11,000 operations for over 5,000 wounded World War I veterans in Britain.

Once revered as the first woman in space, Russian cosmonaut Valentina Tereshkova has since become a contentious figure as she has fought to keep President Vladimir Putin in power.

A Native American woman who fostered peace between the Powhatan people and English settlers in the 1600s, Pocahontas paid dearly for her kindness.

The future Queen Elizabeth was barely a teenager when World War II threatened her nation, but she was determined to do what she could for her country — and she soon became the first female member of the royal family to enlist in the British Army.