In this Aug. 6, 1945 photo, survivors of the first atomic bomb ever used in warfare are seen as they await emergency medical treatment in Hiroshima, Japan. On two days in August 1945, U.S. planes dropped two atomic bombs, one on Hiroshima, one on Nagasaki, the first and only time nuclear weapons have been used. Their destructive power was unprecedented, incinerating buildings and people, and leaving lifelong scars on survivors, not just physical but also psychological, and on the cities themselves. Days later, World War II was over. (AP Photo)