Propoganda
You can't really see from this picture, but the mural on the wall shows an ideal scene of communist utopia, with happy children, labour movements, farmers, etc all rejoicing in the streets. In recent times, the picture below has been added which is a blow up of a photo taken during a huge demonstration (300 000 people) encompassing both east and west Berliners, where Soviet tanks simply bulldozed the crowd to break it up. Utopia, eh?