One thing i always wondered was why they couldn't have dropped the bomb on some unpopulated bit of japan, rather than a city. I'd imagine it would still have made the same point.. and the japanese would still have realised that they had no chance against such firepower. Wouldn't they?
That's struck me, too. They should've tried blowing up some uninhabited area or something before dropping bombs on cities. Just out of curiousity, how many a-bombs did they have ready?