I was walking to Riften and followed a river, I noticed a tower and went inside, it was an abandoned prison. After killing a few ghosts and looting the place I found a different exit out of there to what I had came in.
This was the moment - I emerged next to an amazing waterfall, crashing down onto the rocks below. The Aurora Borealis lit up the night sky, it was spectacular. I walked to the edge of where I was standing just outside the exit and saw the famous Khajitt standing there being cool as usual. This thread doesn't really do justice to what I saw, but believe me, if you had seen it you would feel the same.
Bethesda, you have made a masterpiece, I commend you for it.
This was all on 360 by the way, so our 6 year old hardware is quite capable of generating amazing scenes.