While Juneteenth began as a local celebration of Texas' last slaves being freed on June 19, 1865, it has since evolved into a worldwide celebration of freedom.

How lies and gross negligence contributed to the Space Shuttle Challenger disaster, one of the worst disasters in NASA's history.

Also known as the robber crab and terrestrial hermit crab, the Indo-Pacific coconut crab reigns supreme as the largest arthropod on Earth.

"Black Wall Street" was once the United States' wealthiest African-American neighborhood. But during the Tulsa Race Massacre of 1921, a white mob destroyed the whole thing in just one day.

Drawn together by shared childhood trauma, Henry Lee Lucas and Ottis Toole became lovers — then serial killers who terrorized America in the 1970s.

In the late 1970s, up to 3 million people died in the Killing Fields of the Cambodian genocide. This is what it looked like.

The Ukrainians call the famine the "Holodomor," a name that means "murder through starvation."

These rarely-seen photographs of the Kent State Massacre provide a harrowing look at the day the '60s died.

How "Wild Bill" Hickok rose from humble Quaker roots in Illinois to become a legendary lawman and gunslinger of the Wild West.

While being on the spectrum can sometimes create challenges, these famous people with autism have been able to use their unique way of seeing the world to achieve great feats.

Adolf Hitler literally trusted Erwin Rommel with his life. He never could have expected that in 1944, the "Desert Fox" would join a conspiracy to assassinate him.