What is this song. All help appreciated. Slow Motion.?

Ok. Ive heard this song dozens of times and once I have heard that beethoven had composed it but im not sure. The song is usually played during a slow motion scene. During some part of this clical song it goes ah ah ah ah. It sounds like it would match a greek theme. The voices making the sound, sound high pitched and almost femine. If anyone can help me out with this song I would be appreciated