Scientists and diplomats have debated the nuclear weapons policy since before the atomic bombing of Hiroshima in 1945. The public became concerned about nuclear weapons testing from about 1954, following extensive nuclear testing in the Pacific. In 1961 and 1962, 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 1963, many countries ratified the Partial Test Ban Treaty which prohibited atmospheric nuclear testing.