After World War II broke out, Nagasaki retained its status as a major seaport and became a very important military installation with many production facilities, primarily shipyards, weapons and steel-smelting plants.
Nagasaki is located in two valleys through which two rivers flow. A mountain range divides the residential and industrial districts and resulted in the city’s chaotic development. Its buildings were located on an area of less than four square miles at a time when the entire city covered 35 square miles.
For many years, Nagasaki expanded without an urban development plan. That is why residential and factory buildings were located as close as possible to each other throughout the entire industrial valley. The Mitsubishi Steel and Arms Works, the Mitsubishi Electric Shipyards and the Mitsubishi-Urakami Ordnance Works were located on the south and north sides of the same street.
Although the air raid caused insignificant damage, many people in the city were worried, and some of them, mostly students, were evacuated to rural areas. The overall population decreased somewhat prior to the dropping of the atomic bomb.
The atomic bomb Fat Man with a plutonium core (using plutonium-239), dropped on Nagasaki, weighed 4.5 metric tons and had a yield of 20 kilotons. The United States had planned to drop the bomb on August 11, but the deadline was moved up to August 9.
At 11:02 a.m. local time, on August 9, the crew of the bomber Bock's Car dropped the Fat Man bomb on Nagasaki. The bomb exploded high above the city’s industrial valley, almost halfway between the two main targets – the Mitsubishi Steel and Arms Works to the south and the Mitsubishi-Urakami Ordnance Works to the north.
The atomic explosion over Nagasaki affected an area of about 43 square miles, including 8.5 square miles of water surface and 9.8 square miles covered by buildings. The remaining areas were sparsely populated, and this helped avoid even greater casualties.
The second nuclear strike in history proved just as devastating as the first one. An official Japanese report assessing the results of the attack in Nagasaki described the city as a cemetery where no gravestone remained intact.
The central section of the Nagasaki Peace Park features a colossal figure of a sitting half-naked man called the Peace Statue. His right hand points to the sky, as if showing the falling bomb, and the left hand extends horizontally, symbolizing peace and forgiveness.
The Atomic Bomb Museum has been located in the Peace Park’s south sector since 1996. The museum’s exhibits make a poignant impression on visitors. A clock with its hands frozen at 11:02, the exact time of the August 9, 1945 atomic blast, has become a symbol of Nagasaki.