The hidden complex outside of Tabasco, Mexico, was discovered using laser-based technology.

"I do wonder if it has something to do with rebirth, and if these children could have been important symbols of that."

During the Manson murders, Charles Manson's followers gruesomely killed actress Sharon Tate and six others in Los Angeles on August 9 and 10, 1969.

Domestic and feral cats along with invasive foxes have contributed to the extinction of at least 25 mammals once native to Australia.

An iconic leader of 1960s counterculture, Tom Hayden went from protesting the American political system to working within it as a member of the California State Assembly and California State Senate.

In 2010, Larry Ray moved into his daughter's college dorm room and began manipulating her friends, forming what became known as the Sarah Lawrence cult.

Around 1 p.m. on October 20, 1967, Bob Gimlin and Roger Patterson saw a seven-foot creature in Bluff Creek, California — and caught their encounter on film.

Neighbors described the Grim Sleeper as "friendly and quiet," but inside Lonnie Franklin's home were hundreds of photos of the women he had brutalized and murdered.

In an incident known as the Phoenix Lights, hundreds in Arizona and Nevada witnessed a fireball go across the sky followed by the appearance of a V-shaped craft.

From early 1900s attacks in the Pacific Northwest to the most recent Sasquatch sightings, these close encounters with Bigfoot will send chills up your spine.

The trove of Titanic artifacts headed to auction all belonged to fifth officer Harold G. Lowe — who saved dozens of lives on that ice-cold night in the Atlantic.