Editor's note: On Aug. 6, 1945, the United States dropped an atomic bomb on the Japanese city of Hiroshima—the first time a nuclear weapon had ever been used for warfare. Just three days later, the U.S. dropped a second bomb on Nagasaki. More than 200,000 people were killed in Hiroshima and Nagasaki. Radiation from the bombings continued to claim lives in the decades that followed, causing birth defects and other health issues among their children.