Aerial photograph of Hiroshima used for the atomic bombing. 13th April 1945.The bomb was aimed at the T-shaped Aioi Bridge (white arrow) in the center of the city. The Prefectural Industrial Promotion Hall on the east side of the Motoyasu燫iver today known as Atomic Bomb Dome爄s below the bridge. On July 25; 1945; an order was issued calling for the first atomic bomb to be dropped on one of the following cities: Hiroshima; Kokura; Niigata; and Nagasaki. The order naming Hiroshima as the primary target was issued on August 2. Japan.