Hannah Upp, who first disappeared in 2008 and then in 2013, has a rare condition known as dissociative fugue, and she hasn't been seen since she vanished in 2017.

Between 1985 and 2000, four bodies were found crammed into barrels in the woods of New Hampshire. Authorities believe they were victims of suspected serial killer Terry Rasmussen.

Pennhurst State School and Hospital outside Philadelphia operated for almost 80 years, but was shut down in 1987 after its overcrowded condition and abuse of patients came to light.

No one batted an eye when Randy Roth's second wife fell off a cliff in 1981, but the death of his fourth wife in 1991 — along with the large insurance policy he had on her life — aroused suspicion.

The Lawrence N. McKenzie sank on March 21, 1890, while carrying oranges from Puerto Rico to New York.

The Beach Boys' Brian Wilson credited Eugene Landy with saving his life amidst his battle with depression and substance abuse in the 1970s, but many say that Landy was far from a hero.

The 34-year-old man from Mexico survived after emergency surgery, but doctors are warning of the dangers of these popular cocktails.

Though Maud Lewis spent decades in poverty, rarely leaving her one-room home in Nova Scotia and battling increasingly painful arthritis, she produced some of the most cheerful folk art in Canadian history.

Tracks in the limestone on Monte Cònero seem to have been left behind by multiple sea turtles fleeing from an earthquake nearly 80 million years ago.

A white tiger believed to have Down syndrome, Kenny went viral online as the so-called "ugliest tiger in the world" — but the truth was much more heartbreaking.