An encyclopaedia told me that RAF bombed Berlin on August 20, 1940, starting the "total war"*, and that Hitler got (predictably) very very pissed and ordered a mass scale bombardment over Britain, of which the famous first London bombing of September 7th (or 9th, go by memory) was only the beginning.
Same encyclopaedia says many historians think the Berlin bombing was a smart move by Churchill, who imagined Hitler would respond with a massive bombing campaign over Britain thus - giving the technology of the times - sacrificing many bombing planes and in a sense making more difficult or impossible a subsequent invasion of Britain.
In fact the Battle of Britain, which until August 1940 was largely, largely, largely being won by the Germans, had a reversal during the bombing campaign so that the number of planes shot down in the two armed forces, by end of 1940, was roughly the same.
Many historians would agree that Hitler never thought to invade Britain in spring 1941, in fact he invaded the Soviet Union and those things are prepared quite in advance.
The bombing raids on London are mainly due to the sagacity and the strategic acumen of Mr Churchill. A reinstatement of the sagacity and acumen he showed about Gallipoli during WWI.
Never knew of 11 warld wars, there were only 2 in my memory . I and II are Roman numerals. 1 and 11 are Arab numerals. It's WWII. One usually pronounces it "second world war". Just like Pope Alexander VI is Alexander the Sixth (not Six), and the XX century is the twentieth century (not twenty). It's cardinal but it's read usually as an ordinal, as a strange custom of life. Exceptions apply. YMMV.
Sorry for the OT.
* Actually not really. Germany had already started a total war against Poland with the shelling of Warsaw. There was no total war between Germany and UK until the Berlin bombing, though.