Communism is the final stage of the political reform started witha revolution, according to Marx. First masses of workers will rebel in a industrialezed country; they will implant a socialist government in order to adapt the country for later changes. After private property is banished, and the people possess everything, thenthere will be no need for government, thus the state will be destroyed, to form a society with no social classes. It important to remember that Marx knew that the mentality of man needed to change in order of this to work. He believe in the concept of the "new man" who was humble and just. It is also important to remeber did not believe in a country alone with this structure, but he believed that the whole world adapt to this change. Given this, it is safe to say that no country has ever achieved communism, and anyone who has a sense of equality do agree with this utopia.
No, Russia was not communist, neither is Cuba.