 Overrun Countries series

The Overrun Countries series was a series of thirteen commemorative postage stamps, each of five-cent denomination, issued by the United States over a fifteen-month period in 1943 and 1944 as a tribute to thirteen nations overrun, occupied, and/or annexed by the Axis Powers during or shortly before World War II.The stamps depict, in full color, the national flags of Poland, Czechoslovakia, Norway, Luxembourg, the Netherlands, Belgium, France, Greece, Yugoslavia, Albania, Austria, Denmark, and Korea, with the names of the respective countries underneath.