14 August 1940, which Hitler code-named 'Adlertag', or 'Eagle Day', was fated to become one of the most significant days in the Battle of Britain. It signified the start of the Luftwaffe's aerial offensive, planned to cripple Britain and clear the path for the German troops ammassed in readiness for invasion. The Luftwaffe sent out waves of unescorted bombers to attack dificult and long-range targets by daylight, hoping to confuse and split the fighter defences with the small but numerous bomb formations. The tactic was a calculated gamble and one that cost the Germans deeply.