When the “Liberty Bell” last returned over the Boulder Valley, I am not the only one who heard the unmistakable sound of its engines and ran outside to spot the arriving Boeing B-17. The Thorian thundering of those supercharged Wright Cyclones would resound off the mountains for miles around and viscerally penetrate the senses. It is a sound rare in aviation today, and nearly lost to history.

War chroniclers have tried to describe this sound multiplied a hundredfold across the English countryside and European cities as the U.S. Eighth Air Force flew bombing missions on a daily basis. A client of mine in the 1990’s, a German woman, told me of her childhood in Dusseldorf, Germany. She had been a Hitler youth and had once presented flowers and a box of candy to Hermann Goering. She described to me the B-17 raids of her childhood, of hearing this fearsome sound slowly build in the air long before the bombers appeared from over the horizon, signaling her family to flee for the shelters. She told of how the bombers approached in massed formations, dimming the sun, filling the entire sky, just before releasing their terrible destruction upon her world.

On a visit in 2007 to Colorado’s Rocky Mountain aircraft operations, The Liberty Bell’s pilot, a lad in his twenties, yet older than most of the World War II pilots who flew the B-17 in combat, explained to me that he and crew were about to fly her to England to participate in a British anniversary observance of D-Day. When I began to recite the route he would fly, he was surprised that I knew. I told him that I guessed he would make fuel stops in Bangor and Presque Isle, Maine, then proceed up to Gander Newfoundland. If the weather and winds were favorable -and no doubt, he would delay the flight of Liberty Bell and not risk this rare bird if they were not- it would be possible to make a non-stop flight from Gander to Ireland or Scotland. The pilot wondered how I knew all that.

My father had made eight such flights in World War II delivering these Flying Fortresses to the U.S. 8th aerospace operations in England. On Dad’s first trip on Halloween, 1942, winds were not favorable and fuel stops were needed in Greenland and Reykjavik, Iceland, before continuing to Prestwick, Scotland. In 2008, Liberty Bell made her flight to England and was received with much fanfare by BBC news. News outlets in the U.S., where this history originated, largely ignored the story. Perhaps those who do not know their own history may be condemned to repeat it.

In aircraft design, aesthetic beauty corresponds with function. Pilots lauded the near perfect balance of flight and handling characteristics of this airplane. Its ability to absorb intensive damage in combat, keep flying, and bring its crew home was legendary. The B-17’s World War II role, in the 8th Air Force over Europe and throughout the world, made it a ubiquitous symbol of burgeoning American power in the world, and the promise of triumph over the Axis forces. The magnitude of human sacrifice and ultimate victory that it brought to the war, made this Boeing model one of the most illustrious and romanticized airplanes in history. Few aircraft components types can be associated with so much human drama.

Liberty Bell made her last flight on the morning of June 13, 2011. With an engine fire over Indiana, Capt John Hess made a successful forced landing in a famer’s field with little damage to Liberty Bell. All passengers and crew exited safely. Yet, arriving fire trucks hesitated to drive on to the wet field that the B-17 bomber had just safely landed upon. As the firemen stood back, crew and passengers watched helplessly as the engine fire reached the fuel cells and the Liberty Bell, an irreplaceable piece of American history, was destroyed.