The Schwerer Gustav (lit. "Heavy Gustav") was a German 800 mm super-heavy railway gun developed by Nazi Germany prior World War II. It was the largest artillery piece ever fielded in combat, as well as the largest artillery by caliber size to enter service.
Originally intended to counter the French's Maginot line of fortifications, the gun never saw use during the Battle of France due to the German army simply outflanked the line and ignoring the defense almost entirely. The gun later saw service as an anti-fortification artillery in the Eastern Front.
While the artillery is incredibly powerful, being capable of defeating any fortifications at the time in one hit, it suffered from the sheer number of resource and time needed to operate, being weighted over 1,350 tons and requiring over 2,500 servicemen to simply laid down the track and assembly to prepare its firing position, it is also has very poor rate of fire of one shell for each 30 - 60 minutes.
Two of these railway gun were built; the first is named "Schwerer Gustav" while the second were named "Dora". Both were destroyed at the end of the war by Germany to prevent capture by the allied forces.
