I'm Carl Azuz, it's great to have you watching.

A couple of hundred miles off the northwestern coast of Africa is where you'll find the Canary Islands.

This archipelago is officially a part of Spain, and that's why Spain's Prime Minister traveled there this week.

He wanted to get a firsthand look at a volcanic eruption on the island of La Palma.

For the first time in 50 years, the Cumbre Vieja Volcano had a major eruption on Sunday.

It wasn't a complete surprise⏤Spanish volcanologists said they detected more than 25,000 earthquakes around the volcano over the past couple weeks.

Still, emergency workers evacuated 5,000 people from the area closest to Cumbre Vieja⏤more than 80,000 in all live on the island of La Palma.

And while officials say no injuries or deaths have been reported from the eruption, some houses have been damaged or destroyed, and at least one highway has been cut off by lava.

Hundreds of firefighters have been mustered to guard against any blazes the flowing lava might cause.

Residents have been told to keep their distance from the volcano; ships have been told to steer clear of the waters around Cumbre Vieja because lava flowing into the sea could be a threat to them.

The Canary Islands are a popular tourist spot for European and other visitors⏤400 of them were evacuated from a hotel in La Palma and taken to another island.

A Canary Islands government official says the eruption of molten lava and ash is likely to continue for days.

With about 1,500 volcanoes on Earth, it's no wonder we worry about these mountains of molten rock.

But why do they erupt?

More than 80% of the Earth's surface above and below sea level is volcanic, and deep below, the Earth's tectonic plates are always moving.

Most volcanic activity occurs where these plates collide.

Deep within the earth, it is so hot that rock slowly melt and become magma.

Because this flowing substance is lighter than the rocks around it, it rises.

When some of these tectonic plates shift, the magma rises even higher.

Some of the magma pushes through the cracks in the Earth's crust⏤at vents and at fissures⏤and reaches the surface where it is then called lava.

What kind of eruption the volcano will have, depends on the properties of the magma.

Thin and runny magma means gas trying to escape can do so easily.

When this happens, the lava will flow out of the volcano.

We've seen this with Hawaii's volcanoes because the lava flows slowly, people can get away quickly, and it rarely results in victims.

But thick and sticky magma is a different story.

There's less room for gases to escape and the pressure mounts.

Gas gets trapped in the magma, which then explodes at the surface.

This is called an explosive eruption, and we've seen it with Mt. Edna in Sicily and Mt. St. Helen's in the US.

10-second trivia: Which of these fish can only survive in saltwater?

Sockeye salmon, Bull shark, Atlantic stingray, or Seahorse.

All of these fish have been found in oceans and freshwater rivers except for the seahorse, which only lives in saltwater.

Seahorses, as you're about to see, are fascinating creatures; they can be as small as an inch or as large as a foot long.

They're found in warm and cold waters all over the world, but they can be threatened by a fishing practice called bottom trawling.

This is when a boat tows a weighted net along the ocean floor.

It's very effective in catching large amounts of popular seafood from crab and shrimp to flounder and whiting, and improvements in the methods and nets used have reduced the environmental problems that bottom trawling can cause.

But according to Amanda Vincent, a university professor and Rolex Awards laureate, bottom trawling is still a danger to seahorses, and she's working to protect them.

I think the first time you ever look at a seahorse, you're fascinated by them; they're almost mythical.

Fabled fish of the ancient gods and now an aquarium favorite.

Meet the Tigertail, the Hedgehog, and the Pygmy, some of the 46 known species of seahorse that scientists have struggled to identify due to their expertise in camouflage, which helps them avoid predators.

They change color when they court; they form permanent pair bonds; the male and female come together and dance every morning.

I mean, these animals are the coolest fish, they really are.

One predator that seahorses haven't been able to avoid is humans.

Their habitats in coral reefs, sea grasses, and mangroves across the world are increasingly under threat.

The biggest single threat to seahorses is bottom trawling, every day.

Hundreds of thousands of trawlers scrape the ocean bottom, and they remove everything in their path, leaving devastation behind and its annihilation fishing, pure and simple, and it has to stop.

Amanda Vincent is a marine conservationist and one of the world's leading experts on seahorses.

She has spent over 30 years studying these tiny creatures with big personalities.

We usually tell people not to touch a seahorse if you see it, but I've had to touch them in my professional work and it's riveting.

You tickle their little tails and they let go of whatever they're holding and they grasp your hand instead.

I mean, when did you last have a fish hold your hand?

It's just a feeling, an instant surge of connection with this animal.

Vincent co-founded "Project Seahorse" in 1996, a conservation and research organization which campaigns for stronger regulations on fishing practices and wildlife trade.

They have succeeded in changing national and international legislation to help protect seahorses and established 35 marine protected areas in the Philippines, home to 10 species of seahorse.

During her research, Vincent uncovered a huge global trade in seahorses, a popular ingredient in Chinese medicine worldwide, including in her native Canada.

We tallied it up to be 20, 30 million animals a year, among about 80 countries⏤it was huge.

In terms of number of individual animals traded, it's one of the biggest wildlife trades by far.

So it was really important to take action.

We then generated the first-ever export controls on marine fishes.

That led to a lot of countries actually closing down their seahorse trade legally.

After a lifelong crusade against harmful fishing methods, Vincent is always on the lookout for sustainable alternatives, and she finds it here in the village of Steveston in Vancouver.

- Hey, you've got spot prawns. - We have live spot prawns.

They're caught by traps⏤no habitat destruction, no bycatch of other animals⏤they're the only shrimp I ever eat.

So we⏤when were these guys fished?

Questioning where your seafood comes from is one way to help protect marine life, Vincent says

If you can avoid eating anything connected with bottom trawling, you will have done a great service to the ocean.

And for Vincent, serving the ocean means making us fall in love with these mysterious mythical creatures.

I find that when you talk seahorses, everybody cares.

Essentially, we're using seahorses to help save the seas; if we get it right for these funky little fishes, we will have done a lot for the ocean.

This is a planet worth protecting.

Tell us how you're answering the call with the hashtag #CallToEarth.

In fact, as part of the new partnership with the Rolex luxury watch company, CNN is highlighting a planet worth protecting with the first-ever "Called To Earth Day".

It takes place on November 10.

If you or your school would like to learn more, please visit CNN.com/calltoEarth.

It's not everyday someone tries to break the world record for the longest piece of string cheese. But hey, at the Weyauwega Star Dairy in Weyauwega, Wisconsin, breaking cheesy records is what they're all about.

More than 1,700 people took hold of the single piece of cheese as it was unraveled from a tractor.

After it doubled back, people held part of a 3,832-foot piece of string cheese history; it was almost three quarters of a mile long.

I know what you're thinking: Carl is about to make some cheesy puns.

And you "cheddar" believe it!

You know I "ri-gotta" "mascar-pony" up and stay linguistically "limburger" by "briely" cutting loose with all the "munsterous" and "gouda" puns you "camombert".

That's the fun thing about cheese puns; we just eat them up.

I'm Carl Azuz, you⏤some of you anyway⏤are watching from Medford High School; it is in Medford, Minnesota.

Thank you for subscribing and commenting on our YouTube channel. That's "mozzer-alla" for CNN.