Tsar Gun (Russian: Царь-пушка) is a huge cannon displayed outside the Kremlin in Moscow, which means the Russian Gun Emperor. In 1586, it was made by casting experts under the orders of Russian Tsar Feodor Ivanovich. Its weight is about 18 metric tons, the total length is 5.34 meters, the caliber is 890 mm, and the outer diameter is 1,200 mm, which is the largest howitzer on the Guinness World Records.