Claim: World War II included a military campaign.

The Blitz , from the German word Blitzkrieg meaning ` lightning war ' , was the name used by the British press to describe the heavy air raids carried out over Britain in 1940 and 1941 , during the Second World War .   The German air offensive was concentrated , aimed at the direct bombing of industrial targets and civilian centres which began with heavy raids on London during the latter phase of the battle for air superiority over the United Kingdom which became known as the Battle of Britain . By September 1940 the Luftwaffe had failed to gain air superiority . The German air fleets -LRB- Luftflotten -RRB- were ordered to attack London , thereby drawing RAF Fighter Command into a battle of annihilation . Adolf Hitler and commander-in-chief of the Luftwaffe -LRB- German Air Force -RRB- Reichsmarschall Hermann Göring , sanctioned the change in emphasis on 6 September 1940 .   From 7 September 1940 , just over a year into the war , London was systematically bombed by the Luftwaffe for 56 out of the following 57 days and nights . On 15 September 1940 , a large daylight attack against London was repulsed with significant German losses . Thereafter , the Luftwaffe gradually decreased daylight operations in favour of nocturnal attacks , to avoid RAF defences . The Blitz became a fundamental night bombing campaign after October 1940 .   Ports and industrial centres outside London were also attacked . The main Atlantic sea port of Liverpool was bombed . The North Sea port of Hull , a convenient and easily found target or secondary target for bombers unable to locate their primary targets , was subjected to raids in the Hull Blitz during the war . Other ports including Bristol , Cardiff , Portsmouth , Plymouth , Southampton and Swansea were also bombed , as were the industrial cities of Birmingham , Belfast , Coventry , Glasgow , Manchester and Sheffield . More than one million London houses were destroyed or damaged and more than 40,000 civilians were killed , almost half of them in the capital .   By May 1941 , the threat of an invasion of Britain had ended , and Hitler 's attention turned to Operation Barbarossa , the invasion of the Soviet Union . The bombing failed to demoralise the British into surrender or significantly damage the war economy . The eight months of bombing never seriously hampered British production and the war industries continued to operate and expand . The German offensive 's greatest effect was forcing the dispersal of aircraft production and parts . British wartime studies concluded that cities generally took 10 to 15 days to recover when hit severely but exceptions like Birmingham took three months .   The German air offensive failed for several reasons . In particular , the Luftwaffe High Command -LRB- Oberkommando der Luftwaffe , OKL -RRB- did not develop a methodical strategy for destroying British war industry : German effort was diverted and dispersed against several sets of industries instead of maintaining pressure on any of them . Discussions in OKL revolved around tactics rather than strategy . Poor intelligence on British industry and economic efficiency was also a factor .