In 1944 and 1945 German rockets were aimed primarily from the Continent at Great Britain. Their aim was not precise and consequently resulted in more than eight thousand civilian victims.  Whether or not as a reaction to this German tactic, the Allies started large-scale bombing of German cities. Berlin had already been bombed in 1940, but this resulted in relatively few deaths. The systematically carried out bombings that were carried out starting in 1942 under the British commander Arthur “Bomber” Harris were of a very different magnitude. The first bombing of Cologne with the code name Operation Millennium took place in May of 1942 and caused relatively few deaths (less than five hundred). For that reason engineers were mobilized to develop incendiary bombs that would cause as many victims as possible. The success of these engineers was evident in 1943 during the large firestorm in Hamburg that caused the deaths of 40,000 people.