What happened at Hiroshima?

At 08:15am on 6 August 1945, the United States dropped an atomic bomb on the Japanese city of Hiroshima.

Three days later, it bombed the southern city of Nagasaki.

It's the only time in history that nuclear weapons have ever been used in warfare.

Now, with conflicts being fought across the world, talk about escalation and the threat of a new nuclear arms race is becoming louder.