Earlier this year, I kept hearing that one of California's most unusual natural wonders

was sitting right outside San Diego.

But when I pulled my car off the road next to a metal fence, behind a landfill, a recycling

center, I started to have some doubts.

Hey, Chuck.

Yes.

How's it going?

Good, Chris.

The entrance to the landfill is not the most impressive entrance to a national natural

monument, but it protects it a little bit.

This is Scientific American Science Quickly.

I'm Christopher and Daryatta.

I've always been obsessed with visiting the more extreme corners of my home state, California.

And back before Google Maps and Instagram made it so easy to see what stuff looked like

before you get there, I'd just stare at this big paper triple A map of the state, find

some place that looked interesting, and drive there in my old Honda Accord.

Those trips took me to places like the floor of a pitch black lava tube near the Oregon

border.

So dark inside, I couldn't see two inches in front of my face.

And all the way up to the crest of the white mountains, wandering the bristle cone pines.

But here is a place just a little over an hour from where I grew up that I'd never even

heard of.

...