system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why did the U.S. drop the bombs (fat man and little boy) on Nagasaki and Hiroshima instead of anywhere else?

I never knew that there was an original target destination that was never hit. Feeling rather ignorant right now. Thanks for the history lesson guys!
gpt
> So why those 2 cities?

Tokyo didn't have two good days for visual bombing in the past so it wasn't considered a good target for such a critical attack.

Hiroshima was almost completely flat and was extremely densely packed both industrial and residential, making the the roughly one mile of blast radius the most effective. Most of the structures were made of wood which meant the resulting fire damage would spread and amplify damage beyond the simple blast of the bomb.

Nagasaki again had closely packed wooden buildings through which fire would spread, but had not experienced widespread bombing earlier in the war. It also wasn't the primary target: The intended target was Kokura but that city was too obscured by smoke and haze that the bombers moved on to the secondary target of Nagasaki.