The Treaty on the Prohibition of Nuclear Weapons (TPNW) is the first legally binding international agreement to comprehensively prohibit nuclear weapons, adopted with the aim of their eventual elimination. The Treaty was endorsed by 122 countries at United Nations Headquarters in New York on July 7, 2017; in order to come into effect, it must be ratified by at least fifty countries; as of January 2018, it has been signed by fifty-six and ratified by five. Contained in its twenty articles are provisions that signatory states must agree not to develop, test, produce, manufacture, transfer, possess, stockpile, use or threaten to use nuclear weapons, or allow nuclear weapons to be stationed on their territory. States currently possessing nuclear arsenals may join the Treaty upon submission of a time-bound plan for the verified and irreversible elimination of their nuclear weapons program. Supporters of the Treaty believe it marks an important step towards a nuclear-free world by outlawing the weapons under international law.