Rachel's English: For some people, "s" and "sh" sound the same. As Rachel explains, the positions for these two sounds are quite different. Learn the difference in tongue and lip position, and practice with minimal pairs.

Department of Homeland Security: This video will help you understand US-VISIT, the layer of security that uses biometrics, such as digital fingerprints, to establish and verify international travelers' identities. US-VISIT procedures apply to international travelers holding a non-U.S. passport or visa.

In this exclusive interview, Shania Twain speaks about re-launching her career, music, and motherhood.

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.

Gaga vs. Beyoncé: Ms. E-B declares a winner in the raging battle of the pop queens. See more videos celebrating Q’s 25th birthday at Q Magazine.

A video by FHM.

"Do stars themselves get starstruck?" Interviewer of the stars Jimmy Carter gets several prominent Hollywood actors to open up in response to this provocative question. Enjoy!

Rachel's English: Practice relaxing the tongue when saying words and phrases with the "n" consonant. Study with Tom!

Samuel Gruber's team films white-tipped sharks and barracuda feeding at night off Cocos Island. Enjoy!

Alexander is showing us contractions of the negative forms of the verb "to be".

Learn about the Big Ben clock tower, which is to London what the Eiffel Tower is to Paris or the Colosseum to Rome: a symbol of the city.

Here's some more stunning underwater footage. This time it's hammerhead sharks and stingrays, a wahoo and some striped eels, all filmed near the Cocos Island in the Caribbean. Take a look!

Alexander Pointer takes us through the conjugations of the verb "to be" in the present tense and explains how to form the contraction (otherwise known as the "short form") for each one.

In this episode, Doc Gruber and a colleague are testing a shark repellent. If effective, it could help save the lives of divers, swimmers and surfers all over the world.

Do you know your Turner from your Warhol? If not, don't worry, London is the perfect place to explore the art world through its wealth of museums. Watch and share Marcus's London story and let him take you on a journey of discovery. This Tate Modern curator is just one of the passionate staff waiting to introduce you to the people and ideas housed within the walls of the imposing former power station. Directly opposite St Paul's Cathedral across the Millennium Bridge, Tate Modern sits on the South Bank among one of the most vibrant new parts of the city.

The team's divers conclude their filming and come back to the surface unharmed. We learn more about current developments in the prevention of shark attacks.