In Hiroshima and Nagasaki, the losses are hard to quantify
The atomic bombs dropped by the United States on Hiroshima and Nagasaki in August 1945 left more than 200,000 dead but 70 years later it is still hard to put a precise figure on the casualties.
Two factors in particular account for the lack of certainty.
To begin with, Hiroshima had about 350,000 inhabitants at the time while Nagasaki had less than 200,000.
However tens of thousands of people, especially women and children, had taken refuge in the countryside for fear of US bombing.
Other inhabitants went to the suburbs in the evening after work and returned to the city the next day.
Secondly, many bodies disintegrated under the impact of the two huge explosions, making an exact count impossible.
According to US Energy Department data, 70,000 people were killed immediately at Hiroshima and 40,000 at Nagasaki.
A more or less identical number died soon afterwards, however, from wounds or the effects of radiation.
A generally accepted toll has since been established of 140,000 victims in Hiroshima and 74,000 in Nagasaki, immediately and in the weeks and months that followed the bombings.
- Survivors -
The number of survivors exposed to radiation in Hiroshima and Nagasaki -- the "hibakushas" -- comes to 174,080, with a peak figure of 372,268 being registered in 1980, according to Japanese authorities.
In a few rare cases citizens known as "niju hibakusha" survived both atomic bombings, with survivors from Hiroshima having sought refuge with families and friends in Nagasaki.
Although each bomb was roughly as powerful as the other, at 15 to 20 kilotonnes, the layout of the two cities was different, with Nagasaki's landscape comprised of hills and valleys. That explains in part why the consequences of the two bombings were different.
In Hiroshima nearly 14 square kilometres (four square miles) were flattened and 70,000 houses destroyed in the densely populated centre of the city.
In Nagasaki nearly seven square kilometres (two square miles) were devastated and the bomb fell on a less-populated industrialised zone, 70 percent of which was razed.
Nagasaki was home to the biggest concentration of Catholics in Japan and the bomb destroyed its 17th century cathedral, killing 9,000 of the 10,000 Christians who lived nearby.