Barack Obama became the first sitting U.S. president to visit the site of the Hiroshima atomic bombing.
Some 140,000 people were killed when the U.S. dropped an atomic bomb on the city on Aug. 6, 1945.
Obama called for a world without nuclear weapons after visiting Hiroshima Peace Park Memorial, where he spent a short time in the site's museum and then solemnly placed a wreath at the arched monument.
