airraid Reason for some sirens Blackout cause Wartime attack Reason to take shelter Reason for a blackout Mission for a bomber squadron London Blitz ordeal Event during the Blitz Cause of a WWII siren Bomb-dropping attack Cause of a W.W. II siren Cause for a siren Luftwaffe blitz Blitz event London ordeal of W.W. II Attack from the sky Top-class bishop to assist attack from above Attack from above Reason for a siren