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.

Our British tour guide Lauren is taking us to Trafalgar Square today — come and join her to learn more about this tourist attraction in central London!

Georgian-British singer-songwriter Katie Melua sings her lovely song "The Walls of the World."

Part Two of an exclusive journey through Middle-earth with the cast and crew of The Hobbit: An Unexpected Journey. Enjoy!

When wolves were reintroduced to Yellowstone National Park in the United States after being absent nearly 70 years, the most remarkable "trophic cascade" occurred. What is a trophic cascade and how exactly do wolves change rivers? George Monbiot explains the process.

Caralie is at Annie’s apartment and they are chatting. They don’t know each other very well so they are curious about what the other person is like.

Penny tries to patch things up between Leonard and Sheldon when they are having a fight, but ends up making things worse!

In a passionate monologue, Linus explains what Christmas is really all about.

Come along with Anna as she tours Covent Garden, St. Paul's Church and Neal's Yard, all in London, while telling of Christmas traditions for Londoners as they relate to these locations.

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

The kids try to catch snowflakes on their tongues, and Linus once again proves to be wise beyond his years.

Meet people on the streets of London who talk about how they spend their Christmas holiday. Enjoy!

Lauren again shares about the weather in this second video, specifically bad weather, or as she calls it, "different kinds of good weather" such as fog, wind, heat, humidity and clouds.

In this beloved story, a princess learns that all actions have consequences and many things are not what they seem. Part 1 of 2.

Rozalia Project knows all about marine debris. Do you? Take a look at their wrap-up video from Expedition CLEAN on the Gulf of Maine in August of 2014.