The Hiroshima Peace Memorial Museum exhibits many articles remaining from the atomic bombing. It also displays records and photos showing the actual horrors of the bombing.
It was at 8:15 AM on August 6, 1945 that an atomic bomb was dropped on Hiroshima. At the moment of explosion, the bomb eliminated intense thermic and radioactive rays. Almost the entire area within 2 km of the hypocenter was completely destroyed.
More info
Find out more about Hiroshima Peace Memorial Museum.