Wildlife cameraman Gordon Buchanan explores life in the ocean as cameras designed to withstand the pressures of a life at sea take us out onto the water. They unveil a fascinating underwater world, much of which is out of reach to regular camera crews.In Cape Verde, Gordon starts the adventure with a look at one of the world's largest populations of nesting loggerhead turtles. He then heads to the Bahamas with Caribbean reef sharks, California to see young elephant seals and the British Isles to attach featherweight cameras to a squadron of gannets.