This is definitely a propaganda film in Russia. I would say the main theme is unity. Mary is an American who is performing in a Russian circus. Throughout the film Mary starts to become more and more Russian as the time goes on. In the end Von Kneishitz (the German) is chasing after Mary's baby (who is half-black) and show the Russians that the star, Mary, whom they've all been cheering for is less than human so to speak. The Russians don't care, in fact they say, "Who cares?" Their culture is all one and there isn't any differences between the people. This film came out before WWII and definitely sets up the Germans as the bad guys. Overall this movie was entertaining. It's interesting to see a propaganda film but the storyline was quite weak.
Review of The Circus
