Eye of Sauron
Look deep into this eye and all becomes clear. From my point of view, what we're seeing is the tower of Sauron itself. When Samwise (or perhaps it was Frodo sitting on Amon-Sul?) described the eye as it chased him, I believe one of the things noted was a red "beam" shooting out from the heart of Mordor. It would seem logical that this could have been coming directly from the side of the tower of Sauron itself. In this image, you can see the brick outside of the eye (with some very nice firelight on the edges of those bricks) and if you look closely, what appears to be Sauron himself. I can't quite be sure, but he appears to only have 3 fingers on the hand held up to his face (missing ring finger on the right hand). It's impossible to tell with this small of image whether or not it is simply an artifact, but I think it was actually intended. Also "inside" the image we can see two fire braziers burning to either side with walls behind them. Sauron himself is sitting on a throne (the tall things sticking up are the posts of the throne). A very complex and engrossing image which draws you in for more and more detail. Extremely well done!
Book: The Lord of the Rings