Once it became clear that Germany could not defeat the RAF and achieve air superiority, Hitler tried another tactic. On September 7, 1940, the Luftwaffe launched its first nighttime attack on London. The wail of the air raid sounded across the city, warning Londoners of the danger and driving them to take shelter. Planes darkened the skies above London and bombs exploded in the streets. The Blitz, the German bombing of London and other major British cities between September 1940 and May 1941, had begun. Though the Germans soon abandoned plans for an invasion of Britain due to an RAF victory in the Battle of Britain and the approaching winter, they did aim to disrupt manufacturing, transportation, and administration systems in London, while also striving to break civilian morale and to encourage the British government to seek peace terms. In London alone, the bombing killed tens of thousands of civilians and destroyed more than two million homes.