Schwerer Gustav (English: "Heavy Gustaf") was a German railway gun. It was developed in the late 1930s by Krupp in Rügenwalde as siege artillery for the explicit purpose of destroying the main forts of the French Maginot Line, the strongest fortifications in existence at the time. The fully assembled gun weighed nearly , and could fire shells weighing to a range of . The gun was designed in preparation for the Battle of France, but was not ready for action when the battle began, and in any case the Wehrmacht's Blitzkrieg offensive through Belgium rapidly outflanked and isolated the Maginot Line's static defenses, eventually forcing the French to surrender and making their destruction unnecessary. Gustav was later deployed in the Soviet Union during the Battle of Sevastopol, part of Operation Barbarossa, where, among other things, it destroyed a munitions depot located roughly below ground level. The gun was moved to Leningrad, and may have been intended to be used in the Warsaw Uprising like other German heavy siege pieces, but the uprising was crushed before it could be prepared to fire. Gustav was destroyed by the Germans near the end of the war in 1945 to avoid capture by the Soviet Red Army.