Plastic pollution poses one of the biggest known threats to the ocean and all related ecosystems. Pollution comes in many forms, and agriculture is one important key to bringing about necessary change. All of us are key players, since we all eat food.

Ellis Island, the U.S. gateway to immigration from distant lands, has been reopened to visitors, following significant damage from Hurricane Sandy. A visit there, and to the nearby Statue of Liberty, can be emotional, even for those born in the U.S.

Benedict Cumberbatch solo rappels down a cliff with some encouragement from Bear. In Running Wild with Bear Grylls, Bear is taking it up a level by teaching his celebrity guests essential survival skills that they'll have to master and then prove they can use in a high-stress situation.

The great white shark and killer whale are both infamous marine predators. Normally they leave each other alone, but one day, biologists off the cost of California witness something unprecedented.

Several boats converge near the largest of the Farallon Islands when killer whales are spotted. But what they think is a young killer whale turns out to be a great white shark.

Here we see a simulation of how the attack happened, and find out what effect it had on the population of great white sharks around the Farallon Islands.

How do sharks communicate? Particularly, how would the sharks around the Farallones all know exactly when to evacuate? Scientists who are working on "shark repellent" may have an explanation.

Although no one will ever be completely certain why it occurred, many things have been learned about both species from the attack.

National Geographic filmed South African penguins in their natural habitat. One penguin turns to crime in order to furnish the nest and keep his mate happy.

Fascinating footage, our journey begins in Alaska's Katmai National Park, both inhospitable and beautiful. We observe brown bears as they hunt salmon, track the rare glacier bear, and then continue south to British Columbia on our hunt for the rare Kermode bear, also called ghost bear or spirit bear.

Our journey begins in Alaska's Katmai National Park, both inhospitable and beautiful. We observe brown bears as they hunt salmon, we track the rare glacier bear, and then we continue south to British Columbia on our hunt for the rare Kermode bear, also called ghost bear or spirit bear.

More stunning footage from Alaska shows, up close and personal, the brown bears in action - hunting for salmon and caring for their young. Enjoy!

Observe more stunning footage from Alaska of the bald eagle and the black bear. And finally catch a first glimpse of the rare glacier bear. Enjoy!

In summer, mother bears and their young cubs can be spotted on the plains near Hallo Bay in Alaska's Katmai National Park.

Catch glimpses of sockeye salmon, also called red salmon, as they make their way upstream in a migration known as the "red flood." Also included is footage of dippers, which are some of the only songbirds that search for food on the bottom of a body of water.

In order to fatten up before winter sets in, brown bears feast upon salmon migrating upstream to spawn. Enjoy!.

In this episode, we see how the bears coexist with other creatures in their environment, and also learn about the role of the bear in Tsimshian lore. Enjoy!

The salmon that make it upstream mate and then die of exhaustion. Meanwhile, many other animals are lurking and waiting to feed.

In this final installment of the series, a white Kermode bear encounters a black bear while fishing. Observe their behavior. Look and see for yourself what ensues!

Wild Sharks continues in the mangroves of Bimini Island, the islands most valuable asset, as we learn about and follow mating nurse sharks and other ocean wildlife, including eagle rays and remoras.

Sam Gruber's team of biologists capture, tag and release a juvenile tiger shark. Then they track it electronically into the mangroves, an ideal location for their research.

Gruber's team of researchers work day and night. In this episode they record a shark's vital statistics while it's in a state of tonic immobility. Before releasing it, they take a DNA sample. Enjoy!

At times, Doc Gruber's research requires the team to dive right into shark-infested waters! Their line of work certainly isn't for the faint of heart! Enjoy.

Nathalie and Jim get up close and personal with tiger and lemon sharks, trying to get the best footage while taking care not to disturb or excite the dangerous animals.