I’ve captured this photo at Roca Partida, an volcanic rock who comes up from 2000 meter of depth. Roca Partida (English: Broken Rock) is the smallest of the Revillagigedo Islands in Mexico. It is uninhabited, with an area of only 1.4 hectares (3.5 acres): http://en.wikipedia.org/wiki/Roca_Partida
This place is famous for extreme clear water (otherwise it would be impossible to get a scenery like that) and its Pacific Manta Rays (Manta hamiltony) cruising arround the extinct volcano. by, Norbert Probst.