T-12 Cloudmaker

The T-12 (also known as Cloudmaker) was a 44,000 lb (20 t) tritonal-filled, nose-hardened earthquake bomb developed by the United States from 1944 to 1948 and deployed between 1949 and the withdrawal of the Convair B-36 Peacemaker bomber aircraft in 1958. It was one of a small class of bombs designed to attack targets invulnerable to conventional bombs, such as bunkers and viaducts. It achieved this by having an extremely thick, hardened nose section designed to penetrate deeply into the earth before exploding and then damage the target by the resulting shock wave.