Commemorative coins were released in the USSR between 1965 and 1991. Most of them were made of copper-nickel alloy, but there were also silver coins, gold coins, palladium coins and platinum coins. All of the coins were minted either by the Moscow Mint (Московский монетный двор, ММД) or by the Leningrad Mint (Ленинградский монетный двор, ЛМД). Certain parts of the mintage of almost each coin were minted using the proof coinage technology.