The high desert, harsh and largely untouched, stretches for miles in every direction at Lava Beds National Monument. Foxes live here in the brush, with bears and mountain lions and coyotes, rattlesnakes and lizards and all sorts of birds. In all, almost 300 animal species make this unforgiving place their home.

Underneath the stark landscape, in caves formed tens of thousands of years ago from the lava of Medicine Lake volcano, the place glows with life, too. Literally.

More than 700 caves pock the earth under Lava Beds, some 20 miles south of the Oregon border in northernmost California. In two of them, mysterious, microscopic bacteria cling to the surface of the lava rock.

It’s dark down there, so even veteran cavers can miss the show if their lights are trained in the wrong spot. But shine some light in Golden Dome cave, or in parts of the Hopkins Chocolate cave, and the bacteria make the rock sparkle with gold and silver.

“It’s this really spectacular, unparalleled feature,” says Kenneth Doutt, a ranger at Lava Beds and nearby Tule Lake. “It’s pretty expansive. It’s not like the whole cave is covered in these microbial mats. Rather, you have certain areas that have smaller little patches of it. Or you’ll have an entire ceiling that is covered. A large room. Maybe the size of a classroom.”

Water beads on the bacteria — they’re officially hydrophobic bacteria — reflecting and intensifying the light, creating a glow that is both breathtaking and exceedingly fragile. The bacteria grow in thick “mats,” but a mere touch or an inadvertent bump can wipe out the bacteria, and it can take more than 40 years to grow back.

The sight is stunning, but it’s not for everyone. The two caves that boast the opulent-looking walls and ceiling are rated “moderately challenging” and “most challenging” by the rangers at the monument. (Hopkins Chocolate cave, by the way, is named for 19th century caver E.L. Hopkins, and it combines the golden glow of the bacteria with a mud-infused lava that gives the rock a rich, brown, chocolatey hue.)

A wide array of wonders

Even if you can’t handle those caves, Lava Beds is a playground for spelunkers from the amateur and more professional ranks. Visitors can start with Mushpot cave, the only cave with electricity and paved trails. Another cave, Skull cave, has 80-foot ceilings. And visitors can progress to caves with trails that are barely trails, and caves with trails that are only a foot high. Lava Beds has 20 so-called “developed” caves; some, like the fantastic Crystal Ice cave, are restricted.

As for the other 680-plus caves? They’re rarely explored. Some may have not been explored at all. Some, in the miles and miles of underground lava tubes, have yet to be discovered.

And most are fair game for the brave of heart and the careful afoot.

“Some of them, you can go into. Some you can’t,” Doutt says. “These are very, very sensitive resources. We want to do our very best to preserve them. You have some that have ice formations in them, you have some that have hibernating bats, some have maternity-colony bats ... so, for various reasons, we do close off some caves.

“But generally, if you know where one of these back-country caves are, and if you have the appropriate gear with you ... and you find a cave and there isn’t any information telling you not to go in, then you’re welcome to explore it.”

All of this is part of a land with sweeping above-ground views and a horizon-to-horizon nighttime sky that mimics the glow underneath.

Off the beaten path

Lava Beds is not really on the way to anywhere. The closest town, Tulelake, has a population of under 1,000. The closest big town is Klamath Falls, Oregon, about an hour away.

Whicg means that, for much of the rest of the year, Lava Beds is relatively (and refreshingly) empty. Yosemite — about an eight-hour drive south — has had more visitors in the past two years than Lava Beds has had since records have been kept. (Visitors started being counted in 1934. Lava Beds opened in 1925.)

“You can go into a cave,” Doutt says of the slower months in the year, “and there’s a good chance that you’re not going to see a single other person in that cave.”

That, alone, could make Lava Beds National Monument worth the trip.

A cave glows gold in a remote corner of California
At Lava Beds National Monument, wonders sit above and below the high desert.