This is a fountain. The water flows from the top and trickles over the sides. When the water splashes on the pool below, it creates bubbles across the surface of the water. This is one of those bubbles. When I took this image, I thought, 'I'm finished taking photos...I'm putting away my camera...it doesn't get better than this.' And in the same time it takes to pop a bubble, I discovered I was wrong.

Nikon D40
ISO 200, 8.0, 1/250, f/200mm