John Kerry, speaking in Japan
Media playback is unsupported on your device
Video

Kerry: Hiroshima's history must serve as a warning

US Secretary of State John Kerry has spoken of the personal impact that his historic visit to the Hiroshima memorial in Japan has had on him.

He is the first US secretary of state to ever visit Hiroshima, where around 140,000 were killed when the US dropped an atomic bomb in 1945.

Go to next video: A brief history of nuclear warfare