The star of the film Elf, Will Ferrell, returns to Billy on the Street for a very special holiday lightning round! Watch how New Yorkers react when Will and Billy demand holiday cheer!

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.

Canadian singer Michael Bublé talks about what it means to him to record the holiday classic "Have Yourself a Merry Little Christmas."

Santa has his hands full right now, so talk show host Jimmy Kimmel is helping him figure out which children belong on the naughty list by hooking them up to a fake lie detector.

First lady Michelle Obama met with Melania Trump at the White House on Thursday as both families prepare for the transition.

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.

Enjoy the video for the song "Animal Instinct" from the Irish rock band The Cranberries.

To help prepare the First Lady for life after the White House, Ellen took her to CVS Pharmacy to pick up a few things.

Rosetta revisits the exciting scientific discoveries she has made during her time at Comet 67P/Churyumov-Gerasimenko, including the successful search to find Philae. Now it's time to start preparing to descend to the comet for the end of her extraordinary mission.

Voters in New York City talk about what they fear in a Trump presidency.

Sandra Bullock gives us the scoop on her new family friendly film "Minions" and gives her best Minion impression.

The male characters of the hit TV series How I Met Your Mother are constantly helping each other get into and out of situations. The book Bro on the Go contains the code of honor necessary for maintaining such friendships.

This quirky ad from New Zealand Air employs characters from J. R. R. Tolkien's Middle-earth trilogy. Enjoy!

A British Gas video featuring Amanda Lamb with tops tips on preparing your home for the winter, including information on bleeding radiators, insulating pipes, and checking boiler pressure.

Dana: Six funny ways you know you're in the U.S. that I noticed while back over there this past January.

UNICEF Goodwill Ambassador Katy Perry delivers a special weather report on the devastating effects of climate change for the world’s children.

The song "Airplanes" is a collaboration between American rapper B.o.B, and Hayley Williams, lead singer of American pop punk band Paramore. Enjoy!

Barney never fails to impress the group with the lengths he'll go in order to get a woman interested in him.

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.

In this episode of SciShow Kids, Jessi talks about how solar eclipses occur, and why they can only be seen from certain locations.

Seattle artist Matt Sellars shows off the Clovis Point, a skateboard of his own design. Check out a few scenes from its construction and test drive!

David and Ben Crystal explain why Shakespeare verses read with Original Pronunciation convey very different emotions and open up another level of understanding.

Theresa May gives her first speech as Britain's new prime minister, outlining her priorities for the UK with a focus on domestic issues.

"You're a fishmonger!" By taking a closer look at Shakespeare's words, and particularly his insults, we can see why he is known as a master playwright whose works appeal to audiences all over the world.