Little David & the Harps

Little David was the nickname of an American 36-inch (910 mm) caliber mortar designed to breach the Siegfried Line and then used for test-firing aerial bombs during World War II. With the same calibre as the British Mallet's Mortar, 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.