There are far fewer nuclear weapons now than at the height of the Cold War and the major nuclear powers have all signed up to the principle of disarmament.
But there are other countries that possess nuclear weapons which have not signed up to any arms control treaties.
And with fears of a renewed nuclear arms race between the US, Russia and China, the topic is high on the agenda at this year’s UN General Assembly.
Reality Check’s Jack Goodman takes a look at the facts and figures behind the world’s nuclear arsenals.
Motion graphics by Jacqueline Galvin.
Nuclear weapons: Explained in numbers