Second beam
Notice the second beam way down beneath the bridge at the start? If you get it just right, it's possible to walk off the cliff and land on that lower beam without killing yourself. You won't be able to get back up of course, but it's still nice to go where you've never gone before. Be sure to destroy the Banshees whilst you're down there. Maybe if you move about a lot, you can provoke a Banshee into doing something risky like flying between the two beams?