This is Warrington Crescent, Maida Vale, on the morning of 8 March 1918, after it had been hit by a 1-ton bomb dropped by a Giant bomber the night before -- one of the largest to fall on London during the First World War and the most materially destructive. Twelve people were killed (including Lena Ford, who wrote the words to the song "Keep the home fires burning"). It was the first air raid to come in the dark of the moon and, fortunately, the second-last of the war.
In the 1930s, much was made of the fact that a single bomb had destroyed half a dozen houses and heavily damaged a couple of dozen more, as the above map shows: multiply one bomb by hundreds and repeat as necessary and you've got a knock-out blow. Basing your forecasts on a few outliers like this is not always sensible.
Image sources: L. E. O. Charlton, War Over England (London: Longmans, Green and Co., 1936); Hamilton Fyfe, 'Gothas and Giants beaten back', in John Hammerton, ed., War in the Air: Aerial Wonders of our Time (London: Amalgamated Press, n.d. [1935?]), 520.
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