The Battle of Britain was a military campaign led for the German Air Force (Luftwaffe) to destroy the British air force, just as the Germans had done to the Polish, Dutch, Belgian, and French air forces. The British Royal Air Force (RAF), with the benefit of radar, a new technology, surprised the world by fending off the German air assault. Hitler then ordered the German bombers to change tactics and target factories, civilians, and cities (especially London) in massive nighttime raids designed to break British morale. His decision backfired. In what came to be called “the Blitz,” during September and October of 1940, the Germans caused massive destruction in Britain’s major cities.