Ladies and gentlemen, the next train is now arriving on the Manhattan's found track.

Please stand away to the platform and...

It's April 2008, and I'm on the A-line, headed down to Lower Manhattan.

Once I emerge onto the street, I walk a block west and pass the site where the World Trade Center once stood.

It's now a gray construction site, a gaping rectangle, the size of a city block.

Earth and ramps spiral down and around, and the whole thing looks like an inverted ziggurat. Even after all these years, it hurts to see it. But this is New York,

two blocks further on, and everything changes, including my mood. I'm now in the glass atrium

of the World Financial Center. Street sounds are behind me,

and sunlight fills the space. In the quiet, I'm looking at a giant aquarium, full of coral.

Jellyfish float in one corner and kelp dangles down over spreading fans. There are sea sponges and

wavy things that look like brains. Some of the coral is eight feet tall.

It is this quiet marvel of color and life.

But the most marvelous thing is that this coral reef is made of yarn.

In this episode, we dive into a place where art, ecology, science, and math come together into something extraordinary.

And we'll take an emotional journey, too, from joy to disappointment, devastation, and regeneration.

Welcome to the Crochet Coral Reef.

This is Fiber Nation, tales of textiles, craft, and culture.

I'm your host, Alison Kourleski.

Music Since 2007, the Crochet Coral Reef Exhibition has traveled around the world.

It's the collective handiwork of thousands of people, but it started as the brainchild of one woman.

My name is Margaret Wertheim, and by profession, I'm a science writer and science communicator,

but in the last 10 or 15 years, I've moved into the realm of science and art.

...