The Hiroshima bomb is the most devastating to have been used in real combat. But today’s nuclear weapons are far, far more powerful

Exactly 80 years since an atomic bomb was used in war for the first time, thousands bowed their heads in prayer in Hiroshima on Wednesday, as the city's mayor warned world leaders about the nuclear warheads that still exist today.

Hiroshima marked 80 years since the US dropped an atomic bomb on the Japanese city, holding a ceremony reminding the world of the horrors unleashed.