This 5-cent U.S. postage stamp was issued in 1966 to honor the millennium of Poland's founding and Christianization (966–1966). The design features a crowned white eagle, Poland's national emblem, set against a bold red background. Above the eagle is a cross flanked by the years "966" and "1966", symbolizing 1,000 years of Christianity in Poland. The words "POLAND'S MILLENNIUM" emphasize the historical tribute. A popular piece among both Polish-American collectors and those interested in national heritage commemoratives.