Timeline: Soviet Union

• 20 Dec 1917
  The Soviet secret police force, Cheka (VChK) is established to preserve the Bolshevik Revolution but became an instrument of oppression, responsible for mass arrests, summary executions, and the management of labor and concentration camps. It was disbanded in February 1922.
• 30 Dec 1922
  The Soviet Union is formally established when the Declaration and Treaty on the Formation of the Union of Soviet Socialist Republics is approved by delegates from the Transcaucasian Republics (Armenia, Azerbaijan, and Georgia), Belarus, Ukraine, and Russia.
• 29 Aug 1949
  The Soviet Union performs its first test of an atomic bomb as part of the Soviet Atomic Bomb Project commissioned by Joseph Stalin.
• 12 Aug 1952
  The event known as The Night of the Murdered Poets occurs at the Lubyanka Prison, Moscow, Soviet Union, when thirteen Soviet Jewish intellectuals and writers of the Jewish Anti-Fascist Committee are executed, having been arrested on trumped up charges.
• 29 Oct 1955
  The Soviet battleship Novorossiysk capsizes and sinks after presumably striking a World War II German mine left in the harbor of Sevastopol, killing over 600 crewmen.
• 4 Oct 1957
  Sputnik 1, the first artificial Earth satellite, is launched by the Soviet Union, triggering the Space Race with the United States. Sputnik 1 sent signals back to Earth for three weeks before its batteries were depleted. It continued orbiting the Earth until 4 January 1958 when it was presumed to have fallen back into the atmosphere and broken apart.
• 7 Oct 1959
  The Soviet Union spacecraft *Luna 3* takes the first photographs of the far side of the moon, published by the USSR Academy of Sciences in November 1960.
• 16 Oct 1962
  The Cuban Missile Crisis begins with escalating tensions between the government of the United States and that of the Soviet Union when the Soviets deploy missiles in Cuba. The event lasted for thirteen days until 28 October when an agreement was reached, and full-scale nuclear war averted.
• 21 Dec 1991
  The Alma-Ata Protocols are signed at Alma-Ata, Kazakhstan, Soviet Union, establishing the Commonwealth of Independent States that succeeded the failing Soviet Union and granting independence to Armenia, Azerbaijan, Belarus, Kazakhstan, Kyrgyzstan, Moldova, Russia, Tajikistan, Turkmenistan, Ukraine, and Uzbekistan.
• 25 Dec 1991
  Mikhail Gorbachev resigns as president of the Soviet Union as it collapses following the upheavals and collapse of other pro-Soviet regimes in Eastern Europe and the fall of the Berlin Wall in 1989. The Soviet Union (USSR) was formally dissolved the next day, 26 December.