Count Xavier Dupont de Ligonnès vanished after the murders of his wife and four children in 2011 — and no one has seen him since.

When Rocky Dennis died at age 16, he had already lived more than twice as long as doctors expected — and lived a fuller life than anyone thought possible.

Vivian Liberto was Johnny Cash's first wife and had four children with him. But after their divorce in 1967, she was cast as the bitter shrew who held his talents back.

Measuring nearly a foot wide, the Goliath bird-eating tarantula takes down prey like mice and birds, then liquefies their internal organs.

Zinaida Portnova was a typical teenager in Belarus, but when the Nazis invaded in 1941, she became a deadly resistance fighter who would later be awarded the Soviet Union's highest honor.

Guitarist Chris Pérez married Tejano singer Selena Quintanilla in 1992, but what happened to Selena's husband after her tragic murder in 1995?

In March 1981, Marianne Bachmeier opened fire in a crowded courtroom and killed Klaus Grabowski — the man on trial for murdering her 7-year-old daughter.

After the Nevado del Ruiz volcano erupted on November 13, 1985, 13-year-old Omayra Sánchez became trapped in debris. Three days later, French photographer Frank Fournier captured her final moments.

From the crew's last days of training to the moment the Space Shuttle Challenger exploded, see one of the worst disasters in American aerospace history as it happened.

The bright green flower Fritillaria delavayi has been harvested by humans for medicinal purposes for the last 2,000 years. Now, it's turning brown to camouflage itself.