Going to Hiroshima, hearing the stories of volunteer guides, many of whom are hibakusha, and seeing the history of how the bomb was developed and devastation of the bombing and aftermath of radiaon (in the excellent Memorial Museum) is something that everyone who can, should try to go and experience. Especially world leaders, but also ordinary citizens of the world.
Thank you Mr. Obama for going - I know it meant a lot to the survivors (hibakusha) ad to me, too. At the same time, I agree with the commentator who said we shouldn't spend ay more money 'modernizing' nuclear arsenal! -- let's get RID of them!!!!!