The Grand Slam was the biggest non-nuclear bomb used in World War Two by the British Royal Air Force. (15 min video) Designed by the renowned engineer and inventor, Barnes Wallis who also invented the Bouncing Bomb, used by 617 Squadron in the Dambuster Raids, Operation Chastise.
Designed to be far more powerful than general purpose bombs, these Earthquake Bombs were not designed to hit targets directly but rather penetrate deep underground alongside. The explosion would then create shock waves similar to an earthquake and destroy the foundations of nearby buildings and structures. In March of 1945, fifteen specially modified Avro Lancaster Bombers of 617 Squadron were on their way to a strategic target in Western Germany. The allies had been attempting to demolish the Bielefeld Viaduct using thousands of bombs since the beginning of the war but with no success. This time however, the 15 Lancasters were carrying just a single bomb each, each one capable of destroying the very foundations of the target. One of which was a bomb that the world had never seen used before. The Grand Slam!