This ancient mathematical trickery posits that a mighty hero cannot overtake a tortoise. Zeno of Elea (born c. 490 BCE) is the author of this and other paradoxes.

Sigrid packs her carry-on bag for the flight to Paris. She talks about what she needs to pack, and why.

Larry and Lisa are contestants on "What’s That Word?", a game show that will test their ability to name the opposite words to some common adjectives. Round one is competitive, and nobody leaves empty-handed… but who will get to participate in the bonus round and get a chance at a big cash prize?

Taylor Swift celebrates individuality with a catchy tune and a psychedelically colorful fantasy video. It’s a song that reminds us all that though nobody is perfect, everyone is unique and special in their own way, and that’s a great reason to feel good about ourselves!

Lauren shows us around Brick Lane in East London. Sights include a mosque, street art, and hopping nightclubs.

This power ballad version of a song written by Prince became Sinéad’s international breakthrough hit, topping music charts around the world. Her deep emotions are clear to see in this memorable video, as she explores feelings of love and loss.

The focus of this segment is on animals of the African savanna. We get to see giraffes and elephants, the largest of the land creatures, as well as cheetahs, the fastest.

Actress, author, and neuroscientist Mayim Bialik considers open relationships. While she sees the benefits, there are certainly things she doesn’t “get” about this kind of arrangement, as she sees male and female biology clearly dictating different ideals.

These three words are so similar, but so different! Check out this lesson, too.

Anne-Marie is a successful singer and songwriter, and she believes that all the hard work, discipline, and focus learned while becoming a black belt in karate has prepared her well for her busy life. She clearly loves her teacher Jo, and her sport, in which she has won gold medals at World Championship level.

In this beginner-level video, Luana teaches us about plants. She talks about the functions of the various parts of a plant, and offers tips on watering plants that grow indoors and outdoors.

How do you feel? This beginner video will help you find the right adjective to describe how you're feeling.

Galantis is an electro-pop duo from Sweden. They created “Bones” in collaboration with OneRepublic, a US band. Vocals are by OneRepublic's Ryan Tedder. The video was shot at a California amusement park and was heavily manipulated to make it look as if the visitors to the park are skeletons — fun-loving ones at that.

Mayim shares her doubts and misgivings about open relationships. It seems that for her, the commitment, predictability, and closeness of a monogamous relationship is all together more meaningful and enjoyable.

This is MC Hammer’s signature song and his biggest hit, launching him, along with his flamboyant dance moves and extra wide "Hammer pants", into stardom as the nineties began. First released on the album Please Hammer, Don’t Hurt ‘Em, this tune is certainly untouchable in terms of pure charisma and energy.