It has never been achieved. Any communist will tell you. The only differences between all of us is how long we're willing to put up with the "transition" phase and what we feel that "transition" phase should be like. Some are ok with strong-man fascist dictatorships, as long as they are ostensibly "transitional" phases into communism. I am not. Nor do I consider any fascist state to be in any way communist or leading to communism.