Amid tight security, Group of Seven leaders made an unprecedented visit to the Hiroshima Peace Memorial Museum on Friday — a highly symbolic move arranged by Japan that kick-started a critical three-day summit in the atomic-bombed city and was intended to spur momentum for nuclear disarmament.

The visit, the brainchild of Prime Minister Fumio Kishida, also saw the heads of the G7 nations and the European Union lay wreaths at the cenotaph for victims of the atomic bomb, which was dropped on the city by the United States during World War II, marking the first-ever use of the devastating weapon.

At the Peace Memorial Park — home to the museum — the G7 leaders took part in a tree-planting ceremony and were briefed by Hiroshima Mayor Kazumi Matsui on the history of the Atomic Bomb Dome and the tragic events of Aug. 6, 1945.