Fifty-four years ago today, on February 11, 1971 (January 16, 1971), 63 countries signed the Treaty on the Prohibition of Nuclear Weapons Tests on the Seabed. On February 11, 1971, 63 countries signed the Treaty on the Prohibition of Nuclear Weapons Tests on the Seabed and the Ocean Floor and its Subsoil in ceremonies held in Washington, London and Moscow. The Treaty was adopted by the 25th United Nations General Assembly on December 7, 1970, and entered into force on May 18, 1972.