The biggest mortars ever made were the French "Monster Mortar" (36 French inches; 975 mm; developed by Henri-Joseph Paixhans in 1832), Mallet's Mortar (36 inches; 910 mm; designed by Robert Mallet and tested by the Woolwich Arsenal, London, in 1857) and the "Little David" (36 inches; 914.4 mm; developed in the United States for use in World War II). All three mortars had a caliber of 36 "inches". However, only the "Monster Mortar" was used (at the Battle of Antwerp in 1832).