Little David

Little David was the nickname of an American 36-inch (910 mm) caliber mortar designed and tested between 1944 and 1945 to breach the Siegfried Line. It was also used for test-firing aerial bombs during the final years of World War II. With the same calibre as the British Mallet's Mortar which was constructed in May 1857, it is one of the largest-calibre guns ever built, having a larger calibre than both of Germany's Schwerer Gustav and Dora which were 31.5-inch (800 mm) railway guns.