World’s BIGGEST / MOST POWERFUL GUN ever built! (Heavy Gustav Railway Gun.)

World’s BIGGEST / MOST POWERFUL GUN ever built! (Heavy Gustav Railway Gun.) This is the Schwerer Gustav, or, in English, the Heavy or Great Gustav. And very, very heavy and great it was -- it weighed 1,350 tonnes and could fire a 7 tonne shell to a range of 30 miles. Developed by Nazi Germany in the late 1930s, the Heavy Gustav 800 mm caliber monster canon was explicitly designed as a siege artillery weapon to penetrate and decimate the super thick reinforced concrete fortifications of the French defensive facility known as the Maginot Line.