A-bomb Dome, Hiroshima. The first atomic bomb dropped on Japan on August 4, 1945, obliterated Hiroshima. This building, called the Hiroshima Prefectural Industrial Promotion Hall, was almost 500ft horizontally and 2,000ft vertically from the centre of the blast. The building retained its shape because the explosion was almost directly overhead. But everyone inside was killed instantly. It is now a part of the Hiroshima Peace Memorial Park.