WWII
To end the war.
With the atomic bombing of Hiroshima and Nagasaki.
It ended the war and collapsed Japan's means to make war.
No, because it brought an end to the war.
It brought the end to an cruel war that had the most casualties of any war you could mention.
At the time most people thought it was the right thing to end the war.
As with many other things, the time was ripe. They were going to be built and used by someone, if not in WW2 then soon after.
The atomic bombing of Nagasaki, Japan by the United States at the end of World War II.
The surrender of Japan, caused by the Atomic bombing of Hiroshima and Nagasaki in August 1945
at 8:15 A.M. on August 6, 1945, near the end of World War II.
The United States which remained neutral in the war, entered it and at the end they drooped the atomic bombs ending the war.