By Casey Frye, CCNN Writer

Trevor Cox, a professor of sound from the University of Salford, set the record for the world’s longest echo. How? By using a pistol inside of an old abandoned war fuel bunker in Scotland!
The bunker itself was designed to hold more than 6.7 million gallons of oil in a bomb-proof location for wartime machines.
It’s twice as long as a football field, about 30 feet wide, nearly 44 feet tall, and has walls that are close to 18 inches thick.
Cox shot a pistol inside the gigantic oil tank and the sound echoed on for 112 whole seconds. He explains, “…when we fired the pistol my initial reaction was disbelief; the reverberation times were just too long. I knew immediately we had a new world record.”
In fact, the sound length did set a Guinness World Record, but only 75 seconds qualified. That’s still many times longer than the 15-second record which previously held the title. “It would be interesting to write a piece of music to the pipes,” added Cox.
Images courtesy of the Royal Commission on the Ancient and Historical Monuments of Scotland.