I read a newspaper article where it said that while they were tearing down the stage setup due to the companies that were supposed to be doing so could not show up until later actually found some real unexploded ordinance from the original bombings by the Nazis underneath the planking and stage areas of the Potsdamer Platz Plaza, whether this real stuff was preserved was of unknown origin but I also heard that it surprised the hell out of Roger Waters but I don't know if this is true or not but I think that I remember seeing him say so in a documentary that I saw him in later. This is a fantastic/amazing concert. I own a copy of it.