We also bombed civilian targets because the destructive power of the bomb was still relatively unknown and Hiroshima and Nagasaki had not yet been bombed as they were non military targets. If we had bombed an area that had already been attacked it would have been more difficult to assess the damage that the bomb was capable of and those two cities were &quot;clean slates&quot; so to speak. I can search for citations on this if you like but it&#x27;s been quite a while since I read up on this so it might require some digging through my notes.