Say what you will about the old Soviet Union, but they turned propaganda posters into fine art. I found these examples on a Russian website, Blogdex. If I read the English language story correctly, in the post-Soviet era they are currently used on a magazine called Agitator.
What I love the most is not the message, which for most of the posters is obscured for me because I don't read Russian, but the incredible graphic design and printing of such dynamic and dramatic images. You get Lenin, heroic workers, factory and farm production, all the things that are of another era. Some of the posters celebrate space program successes, and an especially effective one is the blue poster with a red star, commemorating the first trip into space on April 24, 1961, by cosmonaut Yuri Gagarin, .
I'm struck by the Superman-styled images of heroic, muscled men with the hammer-and-sickle on their chests.
The posters weren't used to sell outsiders on communism but for internal use, in factories, schools and offices. I don't know how effective they were as propaganda, but as works of lithographed artwork they are beautiful.