Cold War: Warsaw Pact troops invade Czechoslovakia, crushing the Prague Spring. East German participation is limited to a few specialists due to memories of the recent war. Only Albania and Romania refuse to participate.

The Cold War was a period of global geopolitical rivalry between the United States (US) and the Soviet Union (USSR) and their respective allies, the capitalist Western Bloc and communist Eastern Bloc, which began in the aftermath of the Second World War and ended with the dissolution of the Soviet Union in 1991. The term cold war is used because there was no direct fighting between the two superpowers, though each supported opposing sides in regional conflicts known as proxy wars. In addition to the struggle for ideological and economic influence and an arms race in both conventional and nuclear weapons, the Cold War was expressed through technological rivalries such as the Space Race, espionage, propaganda campaigns, embargoes, and sports diplomacy.

On 20–21 August 1968, the Czechoslovak Socialist Republic was jointly invaded by four fellow Warsaw Pact countries: the Soviet Union, the Polish People's Republic, the People's Republic of Bulgaria, and the Hungarian People's Republic. The invasion stopped Alexander Dubček's Prague Spring liberalisation reforms and strengthened the authoritarian wing of the Communist Party of Czechoslovakia (KSČ).

The Prague Spring was a period of political liberalization and mass protest in the Czechoslovak Socialist Republic. It began on 5 January 1968, when reformist Alexander Dubček was elected First Secretary of the Communist Party of Czechoslovakia (KSČ), and continued until 21 August 1968, when the Soviet Union and three other Warsaw Pact members invaded the country to suppress the reforms.