History's Greatest Mysteries

Despite centuries of sightings and searches, one of the most infamous monsters remains unidentified. As evidence mounts, the mystery endures: Does the Loch Ness Monster exist?

In 1969, one of history's most elusive serial killers terrorizes Northern California. He taunts investigators with cryptic ciphers and clues. Who was he?

On November 22, 1963, President John F. Kennedy is assassinated, shaking the nation to its core. While an initial suspect is captured, many believe there's more to the story.

In 1587, a group of settlers land off the coast of North Carolina on Roanoke Island to establish the first English colony in America-then disappear. Can new technology finally tell us what happened?

In 1997, thousands of people across Phoenix witness a series of strange lights unlike anything they've ever seen. Could this be one of the largest-scale UFO sightings in history?

One of the holiest and most powerful relics from the Bible has been missing for over 2,000 years. While some believe the Ark of the Covenant was destroyed, many people think it's still out there.

In 1930, a New York Supreme Court Justice with close ties to Tammany Hall-and future president Franklin Delano Roosevelt-steps out of a steakhouse and disappears.

Blackbeard, one of history's most notorious pirates, is said to have had a treasure worth millions of dollars. After centuries of searching, the legendary hoard remains missing.

An ancient mechanical device found on a 2,000-year-old shipwreck has become known as the world's first computer. The machine is centuries more advanced than historians thought possible.

Awe-inspiring and mysterious, the pyramids of Egypt are among the most significant wonders of the ancient world. But no one fully understands how they were built, or why.

During WWII, the Nazis stole vast amounts of art, gold, silver and currency, and stashed it across Europe. While some of the plunder has been recovered, much more is still missing.

For centuries, this area of the Atlantic has been the most notorious stretch of ocean on Earth. It's a place where ships, planes and unsuspecting travelers have been lost-without a trace.

It's one of the most famous stories from the Bible: God sends a flood to wipe out nearly every living thing on Earth, except for Noah, his family and the animals he saves in his fabled ark.

It's the only unsolved air piracy case in history: In 1971, a man hijacks a flight, demanding parachutes and $200,000. Can new evidence finally reveal the identity of the hijacker known as D.B. Cooper?

Thousands of people swear they've encountered this legendary North American creature, but Bigfoot has never been officially identified. Does Bigfoot really exist?

It's one of the most famous prehistoric monuments on Earth. But to this day, nobody knows how Stonehenge was built or why.

It is a legendary ancient city, said to be overflowing with gold. As the endless quest to uncover this infamous city continues, will anyone ever find it?

In 2016 a mysterious illness struck dozens of government officials in Cuba. Over the next few years, hundreds more are afflicted. What is the true cause of "Havana Syndrome"?

They've been called the world's greatest archaeological enigma: 2,000-year-old geoglyphs made in the Peruvian desert that span over 50 miles. What is the true purpose of the Nazca Lines?

She was the last pharaoh of Egypt and one of the most famous queens of all time, but her death in 31 B.C. has been shrouded in mystery.

In July 1996, one of the worst aviation disasters in American history left 230 people dead and countless questions unanswered. What caused the explosion of TWA Flight 800?

The history books say Adolf Hitler committed suicide in the final days of World War II, but not everyone believes there's sufficient proof.

During World War II, Japan plundered a fortune worth hundreds of billions of dollars from occupied countries, but to this day its whereabouts are unknown.

It's one of the most infamous crimes in American history: the gruesome murder of a young beauty, unsolved for decades.

In a perfectly planned robbery, thieves steal half a billion dollars in masterpieces from the Gardner Museum in Boston. Who orchestrated the biggest art heist in history-and why?