Atomic bombings of Hiroshima and Nagasaki
Many say that the atomic bombs actually saved many lives in the long run because it prevented the invasion of Japan.  However, Japan had lost a huge part of its food resources and the majority of its navy.  Many of these people suggest that Japan may have lacked the strength to carry out major fighting.  US military commanders made statements during and immediately after 1945 that they believed Japan was effectively defeated prior to the dropping of the bomb.  Before the bombs, Japan offered to surrender, on condition that their leaders had to stay in charge.  America said the Emperor of Japan leader could stay in power, but the Japanese had to take orders from American soldiers placed in Japan, making it an occupied territory.  More people would have been killed in a full battle in Japan.  Some give different guesses of deaths in an invasion and deaths by the atomic bombs, and say that the bombings were not necessary. People still argue about this.  No nuclear weapon has ever been used against a target since August 9, 1945.