December 31: As of this date in 1991 the last official Soviet Union institutions ceased operations and the Soviet Union was effectively dissolved.
The Union of Soviet Socialist Republics (USSR) officially ceased to exist on December 26, 1991 by declaration no. 142-H of the Soviet of the Republics of the Supreme Soviet of the Soviet Union. This declaration acknowledged the independence of the 12 remaining republics of the Soviet Union, and created the Commonwealth of Independent States (CIS).
For most of the Twentieth Century, the activities of the USSR had a huge effect on the United State’s foreign and military policy. Historians have not fully agreed on the dates of the Cold War era, but 1947–1991 is commonly used in textbooks.
The Cold War and its events have left a significant legacy, including major effects on popular culture in the US and Europe. These are especially prevalent in movies and literature around the theme of espionage (such as the internationally successful James Bond film series) and the threat of nuclear warfare that has been used in both dramatic and comedic movies.
TL;DR Civics 