What is the importance of Hiroshima in the book, Bomb?

Hiroshima, Japan was the first city bombed by the Americans with an atomic bomb. The city was typical of the place and time, and people were going about their normal daily routines in the moments before the bomb was dropped. There were some 76,000 buildings before the bomb and only about 6,000 survived. Thousands died in the blast and thousands more died from injuries and radiation after the blast.