Just listening to this on NPR this morning about how and why Hiroshima was chosen.
http://www.npr.org/2015/08/06/429433621/why-did-the-u-s-choose-hiroshima
"The minutes of this committee were declassified years ago — and they show it considered some far less deadly targets. The
initial list included a remote
military installation and
Tokyo Bay, where the bomb would have been detonated as a demonstration.
But the target committee decided those options wouldn't show the world the power of the new bomb.
"They want people to understand that this is something different, and so picking a place that will showcase how different it is, is very important," Wellerstein says......
The committee settled on
two "psychological" objectives of the first atomic bombing: to scare the Japanese into unconditional surrender and to impress upon the world the power of the new weapon.
That second goal was especially important to the researchers choosing the target. The atomic bomb was still top secret, but the scientists had an even more frightening secret. Within a few years, they expected to have a "super-bomb":
the hydrogen (or thermonuclear) bomb. At the time, they believed H-bombs on top of missiles could destroy the world.
Physicist Edward Teller wasn't on the committee, but
a letter he wrote sums up the anxiety of the bomb builders:
"Our only hope is in getting the facts of our results before the people. This might help to convince everybody that the next war would be fatal. For this purpose actual combat use might even be the best thing."
The target committee decided the A-bomb had to kill. At the time, American bombers were already firebombing many cities, killing tens of thousands."