Anti-nuclear protests began on a small scale in the U.S. as early as 1946 in response to Operation Crossroads. Large scale anti-nuclear protests first emerged in the mid-1950s in Japan in the wake of the March 1954 Lucky Dragon Incident. August 1955 saw the first meeting of the World Conference against Atomic and Hydrogen Bombs, which had around 3,000 participants from Japan and other nations. Protests began in Britain in the late 1950s and early 1960s. In the United Kingdom, the first Aldermaston March, organised by the Campaign for Nuclear Disarmament, took place in 1958. In 1961, at the height of the Cold War, about 50,000 women brought together by Women Strike for Peace marched in 60 cities in the United States to demonstrate against nuclear weapons. In 1964, Peace Marches in several Australian capital cities featured "Ban the Bomb" placards.
Nuclear power became an issue of major public protest in the 1970s and demonstrations in France and West Germany began in 1971. In France, between 1975 and 1977, some 175,000 people protested against nuclear power in ten demonstrations. In West Germany, between February 1975 and April 1979, some 280,000 people were involved in seven demonstrations at nuclear sites. Many mass demonstrations took place in the aftermath of the 1979 Three Mile Island accident and a New York City protest in September 1979 involved two hundred thousand people. Some 120,000 people demonstrated against nuclear power in Bonn, in October 1979. In May 1986, following the Chernobyl disaster, an estimated 150,000 to 200,000 people marched in Rome to protest against the Italian nuclear program, and clashes between anti-nuclear protesters and police became common in West Germany.
In the early 1980s, the revival of the nuclear arms race triggered large protests about nuclear weapons. In October 1981 half a million people took to the streets in several cities in Italy, more than 250,000 people protested in Bonn, 250,000 demonstrated in London, and 100,000 marched in Brussels. The largest anti-nuclear protest was held on June 12, 1982, when one million people demonstrated in New York City against nuclear weapons. In October 1983, nearly 3 million people across western Europe protested nuclear missile deployments and demanded an end to the arms race; the largest crowd of almost one million people assembled in the Hague in the Netherlands. In Britain, 400,000 people participated in what was probably the largest demonstration in British history.