Question on a clical/opera evil sounding song?

there is a song that is used in a lot of movies that I hear all the time and it's used mainly when there is a presence or evil or preparation for war. It has lyrics I am sure but I can not make them out. The song sounds like it would be more opera than clical. It's loud and very brutal and it has a not a soft song. I know for sure it was in the movie watchmen but I don't remember what part as it has been a while since I have seen it. I thought it was Flight Of The Valkyries but I am pretty sure it is not.