In light of recent threats, rumors, and heightened fears around nuclear weapons—from news of rogue nations seeking arsenals to the specter of terrorists acquiring "dirty bombs"—LIFE recalls the horrors visited upon Hiroshima and Nagasaki when the U.S. dropped atomic bombs on those cities during WWII. Pictured: A mother and child sit amid rubble and burned, skeletal trees in Hiroshima four months after the city was leveled by an atomic bomb, hastening the end of World War II. Approximately 80,000 people were killed outright; 60,000 more died of injury and radiation by the end of the year.