'Both the Americans and (especially) the British used an area bombardment strategy in which cities were attacked intentionally, with the explicit goal of killing as many civilians as possible.
This was supposed to "break the German will to resist."
Didn't work.'
That's because the bombs were too small. When the US targeted Hiroshima and Nagasaki with the explicit goal of killing as many civillians as possible, only with much bigger bombs, it worked very well. . . . .
The military effect of The Bombs were almost entirely on morale and psychology. The actual destruction and deaths they caused could have been (and were being) duplicated by firestorm raids on the Japanese cities. More people died in the firestorm raid on Tokyo than in either Hiroshima or Nagasaki.
However, the psychological impact of a single plane dropping a single bomb and destroying an entire city must have been immense.