Political map of Russia & the former Soviet Union 8 October 1949 (NATO and the Two Germanys): On April 4, the United States and its European allies formed the NATO alliance (NATO) to counter the Soviet Union. On May 12, the Soviets ended the Berlin blockade (Berlin Blockade). Eleven days later, the western occupation zone of Germany became an independent republic (West Germany). The Soviet-occupied east followed suit (East Germany) in October.    Meanwhile, two other pivotal events occurred: the Soviet Union tested its first nuclear weapon (Soviet atomic bomb project) in August, and the Communists won the Chinese Civil War (Chinese Civil War).