The first nuclear weapon was used in August 1945, after World War II ended. The bombs were thrown at Japanese towns of Hiroshima and Nagasaki, with a three-day interval. They killed over 100,000 people and caused unseen damage to the area. Although nuclear weapons were not used against people after that, the USA conducted tests in the Pacific Ocean which involved nuclear and hydrogen bombs.
As the result, the first anti-nuclear protest movements emerged in Japan in 1954. Following the work by numerous researchers, people started to express concerns regarding the existing and possible health risks. Radiation clouds in the areas where tests were conducted caused food contamination; it especially affected dairy products. The peace movements exploded with mass demonstrations in many countries, mainly Japan, the UK, and the US.
After WWII and during the Cold War period, the global community lived in fear of a nuclear threat coming from the possibility of collision between the USA and USSR. As a result, in 1982, not long before the USSR was broken apart, the largest political and anti-nuclear protest was held in New York. President Ronald Reagan was a major proponent of the nuclear-free world, for which he was criticized by European political leaders.
In general, there were about a dozen key treaties signed since the peak of the Cold War in early 1960s, mainly by the US and Russia (or, formerly, USSR). Other countries participated in this process as well, but the only country that dismantled its nuclear arsenal (without even being a part of the treaty) was South Africa in 1990s. Probably the best known of the documents is the Nuclear Non-Proliferation Treaty (or NPT). According to it, non-nuclear countries would not seek armament, and nuclear countries should dismantle their weapons. In 2013, the deal between Iran and the US was sealed that the Eastern state would not be seeking nuclear weapons. It was considered as a little victory on a journey towards the complete nuclear disarmament.
The major organization which currently fights — in a non-violent way — for elimination of all nuclear weapon in the world is the Campaign for Nuclear Disarmament. The others include the Nuclear Age Peace Foundation, the International Campaign to Abolish Nuclear Weapons, Peace Action, Global Zero, Greenpeace, and the UN Office for Disarmament Affairs. Activists believe that nuclear disarmament will exclude the risk of a nuclear war and contribute to establishment of the global peace.
Nevertheless, there are five official nuclear states: the USA, the UK, France, Russia, and China. Their count of nuclear weapons is approximately 15,650. There are also Israel, India, Pakistan, and North Korea who have these mass destruction weapons. While the major nuclear states publicly support the idea of nuclear disarmament, they are not in rush to get rid of their arsenals. Every country wants guarantees of safety and the means of global control for itself. In other words, countries fear that, by giving up their warheads, they will risk to become weaker.
No matter how powerful the anti-nuclear movement is, there are still myths present which equal nuclear weapons with safety. This is why no major country is now ready to dismantle its arms. Still, there is a hope that, one day, people will live in a nuclear-free world. It cannot be achieved in any other way than through a full consensus between all world countries.