Killer Sharks: The Attacks of Black December

A clash of true oceanic titans sees fights in the remote battlefields of Ascension Island. Tuna are often faster, fitter and bigger than the sharks.

In recent years, an unusual spate of deadly shark attacks has gripped Australia, resulting in five deaths in 10 months. At the same time, great white sharks have begun appearing in growing numbers off the beaches of Cape Cod, Massachusetts, not far from the waters where Steven Spielberg filmed Jaws. What's behind the mysterious arrival of this apex predator in an area where it's rarely been seen for hundreds of years? Are deadly encounters with tourists inevitable? To separate fact from fear, NOVA teams with leading shark experts in Australia and the United States to uncover the science behind the great white's hunting instincts. With shark populations plummeting, scientists race to unlock the secrets of these powerful creatures of the deep in their quest to save people -- and sharks.

See the world's first MRI scan of a great white shark as Ultimate Shark reveals the extreme engineering and predatory abilities of one of nature's most near perfect predators. Hear firsthand accounts of people who survived harrowing encounters, including a surfer who was bitten on the arm and leg, towed by the surfboard ankle strap and miraculously escaped only with minor injuries. National Geographic demystifies the true motives and power behind their behavior.

Atlantis is filmmaker Luc Besson's celebration of the beauty and wonder of the world beneath the sea, expanding upon themes touched on in his film The Big Blue. Combining stunning underwater cinematography and a hypnotic score by Eric Serra, Besson's singular vision defies dialogue or narrative structure to explore ocean life as you've never seen it before.

On a hot summer day, a young man from Philadelphia goes for an afternoon dip; when he is 40 feet from shore he gets attacked and dies; five days later, the Bell Captain at a popular beachside resort is also attacked.