It was a common sight during Desert Storm: grainy black-and-white footage of an Iraqi bunker or hanger slowly getting closer and closer to the screen.
An 8" M110 Howitzer in use during a training exercise. (Wikimedia Commons)
Engineering changes to the initial casing were made via telephone, even as the original barrels were being stripped and reconfigured by machinists on the assembly line. Watch the whole story of the birth of the bunker buster bomb in the video below.