A pair of divers explore the wreck of the Giannis D (originally Shoyo Maru) on the Abu Nuhas reef, Strait of Gubal, Red Sea, Egypt. By British photographer Alex Mustard. He's travelled the world snapping pictures of wrecked ships lying on the sea bed.
Honduras Head south for the Caribbean waters near Utila Island to swim with sharks (without a cage). You'll be hit with a rush of adrenaline, but never fear: whale sharks -- the world's largest fish -- are gentle giants .
Inside the glacier: Astonishing underwater pictures from a maze carved in the ice