In 1968 the Treaty of Tlatelolco came into force, prohibiting nuclear weapons in Latin America and the Caribbean. The treaty was really the first of its kind; the Antarctic Treaty was enacted in 1961, banning not just nuclear weapons but all military activity on the continent, but the Treaty of Tlatelolco was the first treaty to ban nuclear weapons over a wide expanse of populated areas. What is particularly significant is that it holds the weaponized states accountable to a certain extent. The US, the UK, France, and the Netherlands all have territories in the region, and the treaty prohibits those nations from stationing weapons in their territories. The US, the UK, France, and Russia have all signed and ratified the treaty, which binds them from undermining the nonproliferation efforts in any way (the Netherlands does not have its own nuclear weapons, but does store about 20 US nukes).
More recently, the Treaty of Pelindaba established Africa as a nuclear-weapon-free zone in 2009. Thirty-six African countries have ratified the treaty; of all African nations, only South Sudan has neither signed nor ratified. The main aspect of the Treaty of Pelindaba that gives me hope is that some African nations had or were pursuing nuclear weapons: under leader Muammar Gaddafi, Libya intended to begin researching nuclear weapons, and even before the Treaty of Pelindaba came into force, South Africa had dismantled its seven weapons. These are countries that collectively recognized the threat posed by nuclear weapons and attempted to solve the issue via international treaties.
The irony here is that the US had a hand in either encouraging or writing these two treaties. There is a certain illogic to congratulating other countries (and even continents) for banning nuclear weapons while expanding and modernizing our own arsenal, one that prioritizes our own international power over the good of the rest of the world. We can hope that the progressive thinking shown in Africa and Latin American is contagious.