Hiroshima Ground Zero
It took some back-and-forth walking and looking around, but I finally located the street marker indicating the atomic bomb's hypocenter, the epicenter, Ground Zero. The street is a normal street - businesses, apartments - about 100 meters east of the Atomic Bomb Dome. The Americans did not target the Hiroshima Prefectural Industrial Promotion Hall. They targeted the T-shaped Aioi Bridge just meters to the west, because it’s shape was easily recognisable from the air. Without realizing it at first, I crossed that bridge several times going here and there. There are a lot of bridges, because the bulk of Hiroshima occupies silt islands in the Ota River and its branches, south of Hiroshima Station. The bomb detonated about 600 meters above the city. The surrounding low mountains create a kind of bowl shape to conveniently contain and focus the shock wave.
There was only one other group of foreigners who appeared to be looking for the site as well - a French family. I found the marker and was taking pictures and I noticed the family about 20 off to my right at a corner looking lost. But when they saw me taking pictures and appearing to be taking pictures with deliberation, they scurried right over to me and did the same.