What are some movies that talk about the ability mankind has to be good as well as evil?

Basically, I'm writing a thesis about the use of this idea that many fantasy writers have taken, to make the human species look weak because of their natural tendencies to destroy themselves and each other. I know a couple of books that discuss the idea that mankind is also capable of much good, which trumps the evil, but now I am looking for movies. The only one I can think of is Planet of the Apes and I do NOT want to use that one.