What is the latest series of events that we know of within Hiroshima directly before Little Boy was dropped?

by draw_it_now

Confusing title, let me explain:

How late are the known events before the explosion? 1 hour? 30 minutes? 10 minutes? - When was the 'dark spot' in the history of this area before all data in it was destroyed?

Also, what were these events; How much do we know about what occurred, and the people in Hiroshima directly before the bomb was dropped.

When_Ducks_Attack

Your questions still aren't clear. Are you suggesting that there's a stretch of time around the time of the bomb that there's no record of? If so, please define "record," because there were plenty of survivors. Heavens, Tsutomu Yamaguchi was only three kilometers away from Ground Zero, and later survived Nagasaki's bombing.