While reigning as the autocratic ruler of the Congo Free State from 1885 to 1908, King Leopold II of Belgium may have killed as many as 15 million people.

The photo of "Napalm Girl'' depicting nine-year-old Phan Thi Kim Phúc running from a South Vietnamese airstrike shocked the world in 1972. But there's a lot more to her story.

Black Liberation activist Assata Shakur was found guilty of killing a police officer in 1977, only to escape prison two years later and become a political refugee in Cuba.

In July 1947, something crashed on the Foster Ranch in New Mexico. What that object was, what the government said it was, and what the public thought it could be has created a near-mythical confusion that has lasted ever since.

A notorious SS officer and physician, Josef Mengele sent over 400,000 people to their deaths at Auschwitz during World War II — and never faced justice.

After 30 years of solemnly pledging "never again," the world stood by and watched in horror as another genocide unfolded — this time in Cambodia under Pol Pot.

King Aethelred II of England was crowned when he was just 10 years old, and his reign was marked by a series of blunders so bad that he was usurped by the King of Denmark in 1013.

Created with psychology and science in mind, the Stanford Prison Experiment turned regular people into monsters.

Identity politics can lead to some truly violent outcomes. Case in point: the Aryan Brotherhood.

In 1932, Australia went to war against an enemy like none it had ever faced before: the emu.

"Rosie the Riveter" is regarded as a feminist icon today, but the image on which it was based had nothing to do with feminism.