I love the frame of this picture, how the water is completely surrounded by rocks and how that natural element was captured so nicely by the photographer.  The reflection of the light draws the viewer in to the center of the photograph and then the view is lead out of the cave through the back right corner of the photo left to imagine what more is beyond the scope of the lens.  There is so much going on with light and highlights and reflections in this photo that I find it incredibly visual interesting to looks at.  While the majority of the photo is natural tones, the light and the highlights created vibrant blues and greens and reds that are so interesting to the eye.