After World War II, based on the reflections of Hiroshima and Nagasaki, many scientists warned that nuclear weapons would lead to the extinction of human beings. However, the world entered the Cold War era in which the Soviet Union and the United States glared at each other, and their competition to develop massively destructive weapons such as hydrogen bombs and neutron bombs became intense. Moreover, there increased the number of nuclear nations which created new nuclear weapons with the technology of destroying targets faster and more precisely.
The nuclear arms race escalated under the dangerous idea that "As long as we have nuclear weapons, we will not be attacked. Only the possession of nuclear weapons is effective to prevent war."
However, as the fear of nuclear weapons spread all over the world, the Nuclear Nonproliferation Treaty (NPT) was established to prevent the increase in the number of nuclear nations. In addition, specific nuclear-weapon free zones were established, particularly in the Southern Hemisphere, to prohibit the development, production, and acquisition of nuclear weapons based on the premise that any nuclear nations shall not use their nuclear weapons in those specific areas.
From that time and even now, the voice of people who pray for an elimination of nuclear weapons has grown to become a mighty movement for peace.
