In 1971, a man known only as D. B. Cooper hijacked a plane in the United States. He demanded $200,000 and parachutes, and after receiving the money, he opened the rear door of the plane in mid-flight and jumped into the night. Despite extensive searches, he was never found, and his identity has never been determined. Curiously, a small portion of the ransom money was discovered years later along a riverbank, but the mystery of whether he survived to this day remains unsolved.