I'll have to go with Come and See (Idi I Smotri). It's a Russian film about the German invasion of Belarus during World War II, seen through the eyes of a 14 year old who wants to join the Partisans and fight the German invaders. I'd also have to say that it's one of my favorite movies period, it's so amazingly depressing. After watching it, I, and the people that have watched it that I've talked to just feel empty and hollow inside. I've never watched a movie that made me feel as strongly as Come and See, so I'd recommend it to anyone.
http://ia.media-imdb.com/images/M/MV5BMTMzNDA0MjA4M15BMl5BanBnXkFtZTcwMzI2NzAzMQ@@._V1._SY317_CR2,0,214,317_.jpg