Does anyone know what music was used about six years or so ago to advertise the OU? It was a choral/operatic piece involving many singers and gradually rising to a great crescendo.
Since no-one's answered yet, I'll have a stab: from your description, all I can think of is Gorecki's Symphony No. 3. That builds up very slowly, but over about 20 minutes, I think. Just an idea! :)
This doesn't seem to be the correct answer but, having just listened to samples on Amazon, what a beautiful piece of music it is. Thanks for introducing me to it.