This is 99% Invisible. I'm Roman Mars.

You're going to build a wall. It's going to be a real wall.

See that ceiling up there? I mean, this is a wall that if you get up there, you're not coming down very easily.

True. True.

One week into his presidency, Donald Trump signed an executive order to begin building a wall

between the U.S. and Mexico. Trump says it will be, quote, an impenetrable, physical, tall, powerful, beautiful Southern border wall.

But campaign slogans are easy. Reality is harder. That's Joe Richmond from Radio Diaries.

And on this episode with the help of Radio Diaries, we're going to tell a few stories about the physical border

on the Southern edge of the United States. And what happens when instead of people crossing the border,

the border crosses the people. Joe Richmond, we'll take it from here.

In 2006, President Bush signed a law to begin building an 18-foot high fence

along a few key parts of the U.S. Mexico border. The project went by different names,

Operation Gatekeeper in California, Operation Safeguard in Arizona, and in Texas they called it Operation Hold The Line.

Today, that fence looks like a somewhat random dotted line, covers about a third of the entire border.

Now, the border fence has always been controversial, but it's based on a very human impulse

to have an actual physical barrier that marks the imaginary one on the map. It's a simple idea.

And like most things, it turned out to not be so simple.

Hello.

Hello, is this Pamela Taylor?

It is.

So, can you tell me where you are right now?

I'm in my living room. I'm looking out the window. I see my front yard and beyond that is the fence.

...