It's the only unsolved air piracy case in history. In 1971, a man hijacks a Northwest Orient Airlines flight, demanding 4 parachutes and $200,000. He jumps out of the plane with the money and is never seen again. Can new evidence finally reveal the identity of the anonymous hijacker known as D.B. Cooper?

It's one of the most famous prehistoric monuments on Earth. A mysterious arrangement of stones that have adorned the English countryside for millennia. But to this day, nobody knows how the landmark was built or why. Can modern technology finally unlock its secrets? What is the true purpose of Stonehenge?