Hi, this is Anne Strain Champs, with to the best of our knowledge.

The world gets dark in winter.

The light dies and we head indoors.

And traditionally, that's the season when we tell stories about the underworld.

About the gods and monsters, the treasures and secrets hidden down there in the dark.

Well, we're doing a contemporary, scientific version of that today, talking about the literal

underground, one of the least explored parts of the planet. So get your candle or your flashlight,

and keep listening.

It's to the best of our knowledge.

It's to the best of our knowledge. I'm Anne Strange Champs.

How far underground would you be willing to go?

I knew I wanted to write this book and I wanted to think about this realm.

And I called up my friend John Beatty, who's a great climber and a great caver.

And I said, John, I need to know if I can do this.

I need to know if I can be underground and think about the underground.

Take me somewhere and scare the head out of me.

This is Robert McFarlane talking with Steve Steve Paulson, who is just a teensy bit claustrophobic.

So we went for a day's caving down something called Giant's Hole.

This is like a beginner's caving expedition, but it's famous for being very exciting.

And there's something called the Crab Walk in it, this water-worn rift of limestone that folds like a curtain.

And it reaches a point called the VICE.

As you can imagine, the VICE is not a place of great expanse and openness.

...