Kilroy was here, graffiti inside of Fort Knox vault. Kilroy was the name of a rivet inspector of WWII ships which were produced so fast they weren't painted, so his drawings of a face peeking out and the phrase "Kilroy was here", meant to mark where one riveter's work ended and another began (so they couldn't cheat on payroll) were seen everywhere by soldiers on the ships, and then copied by them.
"may have originated through U.S. servicemen who would draw the doodle & text on walls where they were stationed or encamped... German intelligence found the phrase on captured American equipment.. leading Adolf Hitler to believe that Kilroy could be the codename of a high-level Allied spy...War photographer Robert Capa noted a use of the phrase.."On the black, charred walls of an abandoned barn, scrawled in white chalk, was the legend of McAuliffe's GIs: KILROY WAS STUCK HERE".
Kilroy was here is an American popular culture expression that became popular during World War II; it is typically seen in graffiti. Its origins are debated, but the phrase and the distinctive accompanying doodle—a bald-headed man (possibly with a few hairs) with a prominent nose peeking over a wall with the fingers of each hand clutching the wall—became associated with GI's in the 1940s.
Legend #1: This Legend of how "Kilroy was here" starts is with James J. Kilroy, a shipyard inspector during WWII. He chalked the words on bulkheads to show that he had been there and inspected the riveting in the newly constructed ship. To the troops in those ships, however, it was a complete mystery — all they knew for sure was that he had "been there first." As a joke, they began placing the graffiti wherever they (the US forces) landed or went, claiming it was already there when they…