The Soviet passenger liner Admiral Nakhimov sinks in the Black Sea after colliding with the bulk carrier Pyotr Vasev, killing 423.

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.

SS Admiral Nakhimov, launched in March 1925 and originally named SS Berlin, was a passenger liner of the German Weimar Republic later converted to a hospital ship, then a Soviet passenger ship. On 31 August 1986, Admiral Nakhimov collided with the large bulk carrier Pyotr Vasev in the Tsemes Bay, near the port of Novorossiysk, Russian SFSR, and quickly sank. In total, 423 of the 1,234 people on board died.

The Black Sea is a marginal mediterranean sea lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Romania, Russia, Turkey, and Ukraine. The Black Sea is supplied by major rivers, principally the Danube, Dnieper and Dniester. Consequently, while six countries have a coastline on the sea, its drainage basin includes parts of 24 countries in Europe.