Replying to DRAMATIC INSTRUMENTAL MUSIC FOR VIETNAM PROJECT?

I am currently working on a final project for my AP US History class. Mattheuskier and I (AK-Freeskier) were wondering if anyone knew any instrumental music with no vocals and was pretty dark and intense. We were going to use that one song from Ahmet Dadali's segment in Rage's Enjoy, but it was already used by a student in our class. It would be best if it was downloadable for free or something, but let me know if you have any ideas. Thanks!