Largest Caliber Guns Ever Made

The German “Gustav Gun” was the largest caliber rifled weapon ever used in combat.

The U.S. Navy’s Iowa-class battleships were equipped with 20-inch guns.

The Tsar Cannon in Russia is the largest caliber howitzer ever built, but it has never been fired.

The Paris Gun, used in World War I, could fire shells into outer space.

The U.S. once tested a nuclear artillery shell called the "Atomic Annie."