The gutted Hiroshima Prefectural Industrial Promotion Hall (R), currently known as the Atomic Bomb Dome or A-Bomb Dome, is seen after the atomic bombing of Hiroshima, Japan, on August 6, 1945, in this handout photo taken by U.S. Army in November, 1945,REUTERS/U.S. Army/Hiroshima Peace Memorial Museum/Handout via Reuters

In a series of firsts, the U.S. had sent State Secretary John Kerry to Hiroshima in April 2016, and he had said there the memorial was a "stunning" and "a gut-wrenching display." A month later, Barack Obama is set to be the first American president in office to visit the Hiroshima memorial. 

Both Obama and Kerry talked about the complexities of war and the choices made by leaders during one. They also acknowldeged victims of World War II. 

Obama's visit to Hiroshima, he was quoted as saying by CNN, was meant to highlight the "very real risks" of nuclear weapons. 

Hiroshima was the first city to be attacked by a nuclear weapon and the U.S. was the first country to use one. The A-Bomb dome is a symbol of "peace city" Hiroshima. Before the attack it was used as Hiroshima's Prefectural Industrial Promotion Hall. 

Also read: US President Barack Obama to make historic visit to Hiroshima

Today, the memorial is a reminder of the long-drawn suffering of the victims who survived and the 140,000 people who died on Aug. 6, 1945, and on succeeding days. 

A picture shows the wreath U.S. President Barack Obama laid at a cenotaph at Hiroshima Peace Memorial Park in Hiroshima, Japan May 27, 2016.Reuters