From K-QED. We start today's episode hiking in the East Bay Hills near Berkeley.

Reporter Dan Brecky is searching for something

that's baffled locals for more than a century.

The only thing that's assumed is they're ancient.

Scrambling up a steep trail with him is Eric Haven.

This week's question-asker.

But no one knows how ancient.

Like does it go back hundreds of years?

Does it go back thousands of years or older.

Eric's an artist.

He writes and draws graphic novels.

And he was once a producer on the TV show, Mythbusters.

About maybe another 100 yards or 50 yards that way.

Eric and Dan beat their way through some tall grass and come upon what they've been hunting for.

Cool.

A stone wall stretching more than 100 feet.

Aw-inspiring?

It is. Well, I wouldn't say awe-inspiring.

Unless you know how old this is and that no one knows where it came from.

Actually it just looks like an old stone wall.

Just a pile of rocks two or three feet high, but shrouded in more than a century of mystery and speculation.

No one knows who built it.

...