Weighing in at 42,000lbs when loaded with explosives and simply noted as: Bomb, General Purpose, 44,000lbs T-12, the giant "earthquake" bomb is hailed as the largest conventional air dropped munition ever built. Conceived by the U.S. Army Ordnance Department during the closing months of WWII, 57 of the 26 feet 10 inch tall bombs were built by the A.O. Smith Corporation of Milwaukee, Wisconsin. The T-12 was based on successful British 12,000 pound and 22,000 pound bombs which were used against hardened targets such as railroad tunnels, underground bunker complexes and covered submarine bases. The T-12 is reported to be able to penetrate 33 feet of reinforced concrete. WWII ended before the bomb and its intended delivery platform, the B-36 bomber, were ready for service. Its first air drop test came in 1948 from a specially modified B-29 Superfortress Bomber. This example has long served as a symbol of the U.S. Army Ordnance Corps and its historic collection of Ordnance related artifacts, according to the Director U.S. Army Ordnance Museum, Chris Semancik..