 Complete the following phrase:  Two further 1,000 bomber raids were executed over Essen and Bremen, but to less effect than the destruction at Cologne. The effects of the massive raids using a combination of blockbuster bombs and incendiaries created firestorms in some cites. The most extreme examples were caused by the bombing of Hamburg in Operation Gomorrah 45,000 dead, and the bombings of Kassel 10,000 dead, Darmstadt 12,500 dead, Pforzheim 21,200 dead, Swinemuende 23,000 dead, and 