Nuclear weapons completely changed the world after 1945 when they were first witnessed by the bombing of Hiroshima and Nagasaki. Atomic weapons could produce complete destruction that had not been seen before. All kinds of radiation and its delayed fallout made a negative impact on health and environment therefore people felt unsafe and they were living in a constant fear during The Cold War.
The first dropped atomic bombs ever, at Hiroshima and Nagasaki, made Japan to surrender unconditionally and, therefore, this event brought an end to World War II. The U.S. bomber, Enola Gay, asked a question when he saw what he had done - My God, what have we done? That pretty much explains how the atomic bomb changed the world. People in Japan are still dreadful when they think about what happened in August, 1945. The collective memory of this event has a very significant meaning in anti-war movements. People all around the world were afraid, but this massive destruction changed everything for the better because people had not used nuclear weapon for 70 years. Economy and military started to be based on pacifist ideology.