They may be the ocean's top predators, but sharks still face great challenges at mealtime. Watch 10 remarkable shark species including whale and angel sharks on their hunt for prey in various corners of the world. Shark Kill Zone takes an in-depth look at how sharks developed their unique and cunning hunting techniques. What's the secret of their amazing success? What does it take for a shark to catch a meal?

We are back off the coast of San Francisco where an unexpected killing challenged the great white shark's supremacy as the ultimate predator. We return with the whale-watchers who witnessed a stunning act of nature as a killer whale rose to the water's surface with a great white in its mouth. The outcome left biologists mystified but now, with the help of a team of experts, we re-examine this extraordinary incident, and reveal an astonishing new perspective between the ocean's two top predators.