Adolf Hitler's Schwerer Gustav
The Great Gustav as it was commonly known, was a Nazi siege railway gun designed by Krupp in the 1930's and was used in combat in 1941. With a caliber of 80 cm, it is the largest rifled weapon ever used in combat. It is also the heaviest mobile artillery piece ever built with a total weight of nearly 1,350 tonnes. It took a crew of more than 2700 members to get in going with the track laying and to assemble it and prepare it to fire.