From mid 1942 to 1945, so-called Wartime composition nickels were created. These coins are 56% copper, 35% silver and 9% manganese. The wartime nickel features the largest mint mark ever to grace a United States coin, located above Monticello's dome on the reverse. This mark was a large D or S if appropriate for those mints, but nickels of this series minted in Philadelphia have the unique distinction of being the only U.S. coins minted prior to 1979 to bear a P mint mark.