A group of San Diego, CA area surfers unknowingly had a large predator swimming among them as they rode the waves. It was not until a local photographer came home to view his photos that the estimated 12 foot great white shark was spotted diving into the waves mere feet from where many surfers were riding the waves. Shark experts confirmed the sighting based on the photographic evidence. Surfers continue to surf, unfazed by the sighting.
(source)