In 1955, 11 leading scientists and intellectuals signed the Russell-Einstein Manifesto, warning of the dangers posed by nuclear weapons and calling on world leaders to find peaceful solutions to international tensions. This was followed in 1957 by the first of the Pugwash Conferences on Science and World Affairs.
Text of the Russell-Einstein Manifesto
Issued in London, 9 July 1955 Bertrand Russell and Albert Einstein Bertrand Russell and Albert Einstein