In the world of crime, some stories inspire fear, others admiration, and some astonishment. But very few become legendary because they are simply unsolvable.

One of the greatest and most mysterious of these stories is that of "D. B. Cooper",a name that entered history through daring and cunning and vanished without a trace.

On November 24, 1971, a well-dressed man in his forties, wearing a dark suit and tie, boarded Northwest Orient Airlines Flight 305 from Portland, Oregon, to Seattle, Washington, on the Pacific Northwest coast. He identified himself as “Dan Cooper.”

He calmly took a seat in the rear of the plane, ordered a whiskey, and lit a cigarette (smoking was still allowed on planes at the time). Shortly after takeoff, he handed a note to a flight attendant and said quietly: “Miss, I have a bomb in my briefcase. I’d like you to sit beside me so we can talk.”

The flight attendant read the note after he opened the case and showed her the bomb. It contained four demands to be relayed to the pilot and fulfilled exactly:

A ransom of $200,000 in cash upon landing (equivalent to about $1.6 million today).

Four parachutes (two main and two reserve).

A fuel truck ready at Seattle Airport to refuel the plane on landing.

No police involvement via the control tower, under threat of detonating the bomb.

The pilot followed Cooper’s instructions precisely. When the plane landed in Seattle, Cooper calmly waited while it was refueled, then released all passengers, keeping only the flight crew aboard. After receiving the ransom and parachutes, he ordered the plane to take off again toward Mexico City at low altitude, no higher than 10,000 feet (about 3 km),and at a speed not exceeding 150 knots (270 km/h).

That dark, rainy night, somewhere over the forests of Washington or Oregon, D. B. Cooper opened the aircraft's rear door, jumped out with the money-laden briefcase, and was never seen again.

The FBI launched one of the largest investigations in its history. It became clear that the operation had been planned with military-level precision. More than 800 suspects were investigated, most of them retired U.S. Army special forces or U.S. Air Force pilots.

But no one was ever arrested. The mystery deepened further when, in 1980, a bundle of cash totaling only $6,000 was found on the Columbia River’s bank, with serial numbers matching the ransom money.

Cooper became an American folk legend, seen as a hero who pulled off a bold heist without violence or casualties. In June 2016, after more than 45 years of investigation, the FBI officially closed the Cooper case, without ever identifying him or discovering his fate.