Compositing

I learned how to do this in CS4 (I've been combining images for years, but learning to do it in photoshop saves a considerable amount of time). Compositing is where you combine 2 images to make 1. I took the moon from another photo, then copied and pasted it over the bridge. I pasted a second one into the water, flipped it so it would be a proper mirror reflection and used motion blur so it would look like the other reflections in the water. Pretty swell trick!