Michael, that is very cool, the ghosts of times long past. There is an old government TNT and ammunition manufacturing plant just outside Joliet dating from WWII. The shells were stored in specially constructed bunkers outside the plant. The area has been returned to the state and is now a prairie restoration area. About twice a year I volunteer to work there and we take plants in and out the old bunkers. the interior walls contain the same types of graffiti. Names, dates, units, even some "Kilroy was here" drawings.