In recent years, we've seen an increase in the intensity of tropical storms and hurricanes due to global warming. But how and why do hurricanes form? Sigrid provides a basic explanation of this phenomenon.

We continue to explore the phenomenon of hurricanes. Why are they so dangerous? And do they serve any purpose?

Columbus Day has always been a controversial holiday in the United States. In this video, Sigrid goes back in time to get some historical background, which sheds a new light on its significance.

Most Americans don't realize how Columbus Day came to be a national holiday, but it actually doesn't have that much to do with Christopher Columbus, and we might even recognize a connection to present-day events. To recall something Mark Twain once supposedly said, "History doesn't repeat itself, but it often rhymes."

The European Union has been in the news a lot lately, so let's take a look at what it's all about. What is a "union" and what's the purpose of this one?

Let's have a look at which countries are members of the European Union and where they are on the map.

Every day, we get information from lots of different sources. But how do we know what is true and what is "fake news?" In this 3-part series we explore different kinds of information and misinformation.

What's the difference between disinformation and misinformation? And what about misleading information? Find out in this video.

Audio and video sources can be factual, and can be used as evidence, but they can both be doctored, too. When we don't have the facts, we might have hearsay, but can we trust it?

The Enterprise crew rescues con artist Harry Mudd and then is in for quite a surprise when they bring his crew aboard as well.

Nurse Chapel is reunited with her fiancé; but his new obsession leads him to make an android duplicate of Captain Kirk.

In this scene from the Star Trek episode "The Enemy Within," a transporter malfunction creates an evil Kirk, who proceeds to come aboard the ship.

After the Enterprise crew catch a virus that removes their inhibitions, one crew member rambles angrily about how humans don't belong in space and threatens Sulu with a knife.

In the Star Trek episode "The Enemy Within," the Enterprise crew finally get rid of an evil version of Captain Kirk using the transporter.

Kirk tries to literally slap Spock into helping him save the ship, but Spock, infected with the virus, can only lament about spending a whole lifetime learning to hide his feelings. Suddenly, Kirk also seems to be acting strangely.