American poster from 1943 showing a fly dispersing dirt over Philadelphia alongside a plane on a bombing run. The poster was published by the Works Progress Administration (WPA), whose logo you can see at the bottom right, and warns of the diseases carried by flies.
Small prints: A4 (210 × 297 millimeters or 8.27 × 11.69 inches)
Large prints: A3 (297 × 420 millimeters or 11.69 × 16.54 inches)