The road to North Korea's weapons capability follows decades of ups and downs as nuclear states such as the United States and Russia have built up and dismantled their programs. Today, Russia is believed to have the most nuclear weapons, with 4,300. Not far behind is the United States, with 4,000, according to The Bulletin of the Atomic Scientists' Nuclear Notebook . Of the world's approximately 15,000 nuclear weapons, 9,400 are in military arsenals. See the chart below for a visualization of how nuclear arsenals have changed over time.

Source: CNN September 23, 2017 14:48 UTC