Dolphins are one of the smartest animal species on Earth. In fact, their encephalization quotient (their brain size compared to the average for their body size) is second only to humans. But exactly how smart are they? This video shares some incredible facts about dolphins.

Judging by the 26 billion views on over 2 million YouTube videos of them, one thing is certain: cats are very entertaining. But their strange feline behaviors, both amusing and baffling, leave many of us asking: Why do cats do that? Tony Buffington explains the evolutionary history behind some of your cat’s strangest behaviors.

Natalie Fee talks with candor and sensitivity about some usually taboo aspects of daily life and how they affect plastic pollution. She then shows a film clip by artist Chris Jordan that is very difficult to watch, as it shows how litter is killing seabirds.

Natalie Fee talks about impact the clip (at the end of the previous segment) had on her life and how she started out on her journey. One stop on that journey was a music video.

Natalie provides some facts and figures about how much garbage is getting flushed down the toilet in the UK, and goes on to tell us about a successful campaign she spearheaded, aimed at manufacturers of cotton swabs.

Natalie provides some tips for wasting less plastic and leaves us with a slogan to help us rethink our flushing habits. She involves the audience to bring the message home.

Natalie Fee concludes her Ted Talk with a few suggestions for what we can do to reduce how much single-use plastic we are sending into the earth's waterways.

What does the Holocaust have to do with us, anyway? In part two, Roderick Miller, the chair of the nonprofit organization Tracing the Past, gives a talk at TEDxVienna about the Holocaust and contemporary Europeans' perception of the space they live in.

What does the Holocaust have to do with us, anyway? In part three, Roderick Miller, the chair of the nonprofit organization Tracing the Past, gives a talk at TEDxVienna about the Holocaust and contemporary Europeans' perception of the space they live in.

When hit US sitcom That '70s Show finally ended its long and successful run, the actors came together to reminisce and relive the good times and best moments. How did it all get started? Did any of them ever dream that the show would be so popular?

Looking back at the pilot episode from all those years ago, the actors explain why the show made audiences of different ages laugh, and cringe at their own acting skills.

Eric finds that the road to happiness is not without a few bumps as his and Donna's teenage romance becomes an adult relationship.

The cast hadn’t met before filming the show, but there was a good chemistry between them right from the start. When they got together and were having a good time, the viewers knew it, and very soon were also having a good time watching.

Some memorable scenes came when That '70s Show pioneered new camera techniques. They were the first show using “three sixty degree” scenes, bringing each character into sharper focus, often with hilarious results.

The cast recall their favorite moments of a show that didn’t mind pushing the boundaries. A cartoon episode was made, and the “three-sixty” scenes were a huge hit — to the extent that they often weren't even related to the storyline.