When the bombs dropped

The two nuclear bombs that were dropped on Hiroshima on August 6, 1945, and Nagasaki just three days later on August 9 by America ultimately triggered the end of the Second World War and Japan's surrender on August 15.

The dropping of the bombs 75 years ago escalated the horrors of armed conflict to an entirely new level - the devastation being such that nuclear weapons have never been used since.

Countless countries retain their advanced nuclear arsenals to this day for that very reason - as a deterrent - arguing nobody would ever push the nuclear button again.

But moral and ethical debate over the justification for their use at the time - and the fact countries continue to arm themselves with nuclear weapons - continues 75 years on.

The two bombs, delivered by modified Boeing B-29 Superfortresses, killed an estimated 129,000 to 226,000 people, the majority of whom were civilians.

Half of the estimated deaths were in the first day, but large numbers of people continued to die for many months afterwards from the effects of burns, radiation, and other injuries, compounded by illness and malnutrition.

Their use was justified at the time by the estimated high cost of Allied lives of having to invade Japanese territories and Japan itself and forced the nation's surrender.