Raid on Köln – May 1942; Wikimedia Commons
Cologne Germany (Köln) was bombed in 262 separate air raids during WWII, but Operation Millenium, the RAF attack on May 30 1942, was the first Allied “bomber stream” raid with > 1,000 aircraft.
With over two thousand separate fires started by the raid, only Köln’s wide streets and the action of German fire fighters prevented the fires from combining into a firestorm.
411 civilians and 58 military died in the raid. 5,027 people were listed as injured and 45,132 as “bombed out”.
The RAF lost 43 aircraft.