President of the United States, Barack Obama, has visited Hiroshima during his trip to Japan.
The visit means he is the first serving American President to visit Hiroshima.
Hiroshima is the city which was destroyed by a US atomic bomb in 1945.
The bombing is credited with bringing to an end World War Two, but it claimed the lives of tens of thousands of people.
During the visit Obama made a speech to survivors of the attack. He honoured all those who lost their lives in World War Two.
An American B-29 bomber called the Enola Gay dropped the atomic bomb, exploding some 600 metres above the city on 6 August 1945.
On that day alone, at least 70,000 people are believed to have been killed.
Thousands more people died from their injuries and radiation sickness in the weeks, months and years that followed.