Becton, an abandoned 1930s gasworks town by the Thames was used as the Vietnam city of Hue. And we found an area that had the same 1930's functionalist architecture. You couldn't duplicate, oh, all those twisted bits of reinforcement. I found that out in Paths of Glory. We had to copy rocks, but every rock also has an inherent logic you're not aware of until you see a fake rock.
Every detail looks right, but something's wrong.
So we had real rubble. All in all, a tremendous set dressing and rubble job. Lee Ermy a former Parris Island drill instructor originally hired as technical advisor was given the part of Sgt. Hartman after Kubrick observed the way he handled actors during casting session improvisations. Most of the outrageous insults he hurls at recruits were Ermy's own creations.