The Eastern Bloc was the group of Communist states of Central and Eastern Europe, including the Soviet Union and the countries of the Warsaw Pact, including Poland, the German Democratic Republic, the Hungary, Bulgaria, Czechoslovakia, Romania, Albania and Yugoslavia(until Informbiro in 1948). The Hungarian Revolution of 1956 was a spontaneous nationwide revolt against the Communist government, lasting from 23 October until 10 November 1956. Soviet leader Nikita Khrushchev's denunciation of the excesses of Stalin's regime during the Twentieth Communist Party Congress in 1956 as well as the Hungarian revolt, produced disunity within Western European communist and socialist parties.