The earth's bodies of water are the focus of this film about evolution. As the narrator points out, the vast depths of the earth's oceans remain barely explored.

Some and any both refer to an unspecified quantity, but they are used in different situations. Sigrid explains how they work.

Here's a business meeting where not everyone has the same opinion. Even if you can't understand every word, try to grasp some of the expressions the speakers use to agree or disagree.

Sigrid explains the meaning of "prop" as both a noun and a verb. Either one can come in handy.

Bob Dignen introduces the topic of decision-making in international companies, and the various approaches to this.

The narrator explains how the breathtaking rock formations of Antelope Canyon came to be, and why mountains around the world can provide a metaphor for human existence.

The BBC looks at a new and innovative renewable energy invention, Kite Power Solutions. It is estimated that 30 kites could provide electricity for 75,000 homes.

We visit Bryce Canyon, where valuable fossils have helped understand the geological history of the planet. The sandstone spires of the canyon are breathtaking.

Here are some words to help answer the question "Which one?" We distinguish between singular and plural as well as between something close to us and far away.

In this segment, we learn about the role weather plays in the creation of rock formations in the national parks of the United States.

Watch some coverage of the People's Climate March that was timed to coincide with the UN Climate Summit in New York City. The march was attended by 400,000 people.

Geysers represent a very popular tourist attraction in Yellowstone Park. How do they work and where do they come from? And what is sandstone? The video answers these questions.

"One" and "ones" can replace nouns, but are not pronouns. They are prop words. Let's look at how they are used.

Why are some rock formations and animals found on more than one continent? The explanation dates back to the Ice Age.

Why do some of the national parks in the United States resemble the European Alps? Geologist Dr. Robert Darga answers this question.