Communism was a human form of government based on equality and sharing of means of production. Karl Marx, Vladimir Lenin and Joseph Stalin were all pivotal figures in communism's history. In 20th century Spain, a communist republican group were elected to govern.
In July 1936, the Spanish Civil War began when a group of conservative generals revolted against the democratic government out of fear that traditional Catholic values were being undermined and the government was leaning towards Communism. (AUDIO: Fiesta of the Damned)
In 1989, the Communist regimes in Poland, Hungary and Czechoslovakia were overthrown. In Czechoslovakia, it was known as the Velvet Revolution and took place on 28 November of that year. The Eleventh Doctor, Amy Pond and Rory Williams were present for that event, and stopped an alien invasion by the Mavora, with the help of the Golem of Prague. (COMIC: The Broken Man)