<human>:  When did the first nuclear weapons test take place?
<bot>: The first nuclear weapons test took place in July 1945 in the city of Alamogordo, New Mexico. It was a test of the first nuclear weapon ever detonated, a bomb called "The Gadget". The bomb was detonated by the United States government to test the effects of nuclear weapons on the earth's atmosphere. The explosion caused a fireball that was visible from many miles away.