This one is eluding me......

[BlackWolfe]

There is a bump that Williams used long ago, and still occasionally does that I can NOT find out any information about.
The 'song' is two female voices singing in harmony. The version that Williams used I believe had a Harp accompanying
them. You can hear the 'song' in the beginning trailer for the movie "4 Months, 3 Weeks and 2 Days". This is driving
met nuts because I KNOW it has got to be an excerpt from an opera but I do not know which one. HELP!
And thanks.........

[NumyMufn]

This is the bump in question:
http://www.bumpworthy.com/bump_display.php?bid=25
I don't believe it's from a publicly available piece, though, just the library track. 

Should you find out differently please let us know