Chelsea Handler here. This week on the Dear Chelsea podcast, Riley Keough discusses the memoir she co-wrote with her mother, Lisa Marie Presley. But it's also such a gift to be able to sit here and say as an adult woman, I had such a good mother. Yes. That is a gift. I know. You know, she certainly was not like a, I don't know what a perfect mother is. Well, she wasn't a traditional mother. She wasn't a traditional mother.

I am so grateful to have had her as a mother.

To have that kind of love.

Fine. Dear Chelsea, on the IHeartRadio app, Apple Podcasts, or wherever you get your podcasts.

Welcome to Brain Stuff, a production of IHeartRadio.

Hey, Brainstuff. Lauren Boglebaum here.

With winter coming on fast here in the northern hemisphere, I've been thinking about travel.

But not travel through the cold, wet weather.

What if we could reach a beautiful destination via underwater tunnel?

Unfortunately, contrary to what supervillains and molemen would have you believe,

it takes more than some giant machine to build an underwater tunnel.

Even so, for most of human history, we've been pretty tunnel savvy.

Humans have tunneled since the first

cave dwellers decided to excavate a spare bedroom, and the essentials of dig, support, and

advance were well refined by the time the ancient Greeks used tunnels to irrigate and drain their

farmland. Even underwater tunneling is old. Sometime around 2170 BCE, the Babylonians built one of the first known examples by diverting the Euphrates River.

The brick-lined and arch-supported tunnel measured 12 feet high by 15 feet wide, that's 4 by 5 meters,

and provided passage for pedestrians and chariots alike between the

royal palace and a temple some 3,000 feet or 900 meters away. For centuries, tunnels were

employed mainly by miners and medieval sappers, who dug under castle walls to collapse them, hence

the term, undermine. But the advent of canal transport,

and later railroads, gave workers something new to sink their shovels into. The 18th through

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