In the grounds of the Hiroshima A-Bomb Memorial Peace Park, you will find a splendid museum detailing the event, with a strong anti-nuclear weaponry theme, not surprisingly. The pics attached below were taken in the museum:
Pic #1 (top): model of Hiroshima prior to the bombing.
Pic #2 (middle): model of Hiroshima after the bombing - only bits of some ferro-concrete buildings were left standing.
Pic #3 (bottom): a stitched pic of four separate photos I took of a huge display in the museum of the real panorama of Hiroshima a few days after bombing.
For orientation, the T-shaped bridge at left of Pic #1 is shown at the far right of Pic #3. It is partially hidden to the extreme left of Pic #2.
This odd-shaped bridge survived the blast and is still in use today. The A-Bomb was supposed to be detonated above this bridge because it was easily identifiable from the air. The bomb instead exploded 300 metres to the south-east of the T-shaped bridge, at a height of 580 metres, in order to maximise its destructive impact. The time was exactly 8.15am, 6/8/1945, on a beautiful sunny blue morning (similar weather to the day I was there 9/8/2004). The bomber had 4 possible cities to bomb, but Hiroshima got it because it had the best weather for the drop.