History's Greatest Mysteries Season 4

Despite centuries of sightings and searches, one of the most infamous deep-sea monsters remains unidentified. As evidence continues to mount, the mystery endures: does the Loch Ness Monster really exist? And if so, what…

In 1969, one of history's most elusive serial killers terrorizes Northern California. He taunts investigators with cryptic ciphers and clues, leaving police and the public questioning his identity for over 50 years. Can…

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; investigators and amateur sleuths alike have…

In 1587, a group of settlers land off the coast of North Carolina on Roanoke Island to establish the first English Colony in America. But only a few years later, the 115 men, women and children seemingly vanish without…

In 1997, thousands of people in Phoenix witnessed strange lights; this could be an UFO sighting.

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. Could new clues finally…

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. For decades, the politically charged case dominates…

One of history's most notorious pirates, Blackbeard, is said to have had a treasure worth millions of dollars. After centuries of searching, the legendary hoard remains missing. As new evidence is unearthed, the mystery…

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, but its origin and true purpose…

Awe-inspiring and mysterious, the pyramids of Egypt are significant wonders of the ancient world; more than 4,000 years old, they are celebrated architectural marvels, but no one fully understands how they were built or…

During World War Two, 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 nearly 80 years later.

A look at what could cause mysterious vanishings in the Bermuda Triangle, a 500,000 square mile area of the Atlantic where ships, planes and unsuspecting travelers have been lost without a trace.

It's one of the most famous stories from the Bible; for thousands of years the tale of Noah's Ark is shared, but little is known about what happened to the ark.

It's the only unsolved air piracy case in history; in 1971, a man hijacks a Northwest Orient Airlines flight, demanding four parachutes and $200,000; he jumps out of the plane with the money and is never seen again.

Thousands of people swear they've encountered the legendary North American creature Bigfoot, but Bigfoot has never been officially identified; as evidence continues to mount, and photos are scrutinized, the mystery…

It's one of the most famous prehistoric monuments on Earth -- a mysterious arrangement of stones that have adorned the English countryside for millennia; nobody knows how the landmark was built or why.

It is a legendary ancient city, said to be overflowing with gold. For centuries, explorers put their lives on the line searching for it. As the endless quest to uncover this infamous city continues, will anyone ever…

In 2016 a mysterious illness strikes dozens of government officials in Cuba. Over the next few years, hundreds more are afflicted. But investigations raise more questions than answers about this bizarre epidemic. What…

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. The drawings are so massive, they can only be seen from the air. Can new…

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. Cleopatra's body and final resting place have been lost without a trace for over…

In July 1996, one of the worst aviation disasters in American history leaves 230 people dead and countless questions unanswered; it's a tragedy that changes the aviation industry forever.

The history books say Adolf Hitler committed suicide in the final days of World War II, but not everyone believes there's sufficient proof; questions have swirled for decades about his possible escape.

During World War II, Japan plunders 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. There's a long line of suspects, each more mysterious than the next. Can the questions surrounding…

In a perfectly planned robbery, thieves steal half a billion dollars in masterpieces from the Gardner Museum in Boston; it's been three decades since the brazen heist, and an exhaustive search has failed to recover the…