Flag Day, June 1943. U.S. Navy sailors and Army soldiers march through the streets of Oswego, New York, as American flags line the parade route during United Nations Week. With World War II in full swing, events like this served a dual purpose: honoring the flag and reinforcing public support for the Allied war effort. The "United Nations" reference was the wartime term for the Allied coalition, formalized in January 1942 when 26 nations signed the Declaration by United Nations pledging to fight the Axis powers together.