10 Marvels of Underwater Photography Celebrated by National Geographic

What was the first color underwater photo, and how was it taken? What exactly was Jacques Cousteau's influence on the underwater photography field? How were photos taken of the Titanic, 12500 feet below the surface? National Geographic has a fascinating little slideshow of the history of underwater photography, though one question it failed to answer for me is exactly what the photographers say to the fish to get them to smile for the camera. Krill? [National Geographic]