I was struck by a few details I'd never heard before growing up in the US:
1) The center of the detonation was a hospital. It's unlikely they tried to hit the hospital, but the fact remains it was 'ground zero'.
2) A good portion of the hospital's metal frame was still standing and was a focal point of a monument; grass was growing and generally speaking it didn't match up with what I expected to see as 'ground zero' (aka a crater, nothing growing, nothing standing).
3) No active US President has ever visited Hiroshima or the museum there dedicated to the atomic bombings; Carter visited after he was no longer president.
If you have a chance to visit Hiroshima Peace Memorial Museum it's well worth a visit. Quite humbling.
https://en.wikipedia.org/wiki/Hiroshima_Peace_Memorial_Museu...