K-19, the first Soviet nuclear submarine equipped with nuclear missiles, is commissioned.

K-19 was the first submarine of the Project 658 class, the first generation of Soviet nuclear submarines equipped with nuclear ballistic missiles, specifically the R-13 SLBM. The boat was hastily built by the Soviets in response to United States' developments in nuclear submarines as part of the arms race. Before she was launched, 10 civilian workers and a sailor died due to accidents and fires. After K-19 was commissioned, the boat had multiple breakdowns and accidents, several of which threatened to sink the submarine.

The Union of Soviet Socialist Republics (USSR), commonly known as the Soviet Union, was a transcontinental country that spanned much of Eurasia from 1922 until it dissolved in 1991. During its existence, it was the largest country by area, extending across eleven time zones and sharing borders with twelve countries, and the third-most populous country. An overall successor to the Russian Empire, it was nominally organized as a federal union of national republics, the largest and most populous of which was the Russian SFSR. In practice, its government and economy were highly centralized. As a one-party state governed by the Communist Party of the Soviet Union (CPSU), it was the flagship communist state. Its capital and largest city was Moscow.

A nuclear submarine is a submarine powered by a nuclear reactor, but not necessarily nuclear-armed.

A submarine-launched ballistic missile (SLBM) is a ballistic missile capable of being launched from submarines. Modern variants usually deliver multiple independently targetable reentry vehicles (MIRVs), each of which carries a nuclear warhead and allows a single launched missile to strike several targets. Submarine-launched ballistic missiles operate in a different way from submarine-launched cruise missiles.