The East Wing—the newest addition—explained the history of Hiroshima City before the bomb, development and decision to drop the bomb, the lives of Hiroshima citizens during World War II and after the bombing, and ended with information about the nuclear age and efforts for international peace. Included in this section was a model showing the damage done to the city. It had some important letters exchanged between scientists and top leaders of that era talking about atomic development and predicted result of its use.