What's the music often played in doentaries when someone is reflecting or about to face their fears called?

There is a piece of music that is very atmospheric, and is often played in doentaries when people are reflecting on their achievements, or about to face upto their fears or the unknown. I can't remember where I have heard it, but it was defo in a doentary. Any suggestions would be appreciated, and I'll bang them in YouTube and let you know if that's what I mean!