Much of California Caverns’ early history is shrouded in mystery. The indigenous Miwok people were said to have used the caverns as a jail, and there are rumors that a Spanish helmet was once found inside.

In 1850, a prospector named Captain Joseph Taylor was passing the time with target practice on the rocks above when he suddenly felt a rush of cool air on his skin. It was coming from a hole that lead to the caverns he had no idea were gaping underneath his feet. Thrilled by the notion he’d stumbled upon a secret goldmine, Taylor returned the next day with gunpowder and blew the hole wide open to expose the cave’s entrance.

The caverns he found were marble, not gold — but the underworld Taylor had rediscovered immediately captured the public imagination.

“It gave him the idea of charging a pinch of gold dust or a couple of coins and giving candlelit tours — starting this off as the very first commercialized cave in California,” explains Kilbreath.

Finding himself one of the state’s first tourism entrepreneurs, Taylor shrewdly dubbed the caverns Mammoth Cave, after the famous Kentucky cave systems that were drawing attention all over the United States. Afledgling town sprung up around this new tourist attraction, and became known as “Cave City” — a name the caverns eventually took too.

Throughout history, humans have always been thrilled by the idea of underground worlds, and when it opened to the public, Taylor’s cave was a monster hit.

“No powers of description can convey an idea of the immensity of this cave, the grandeur of its lofty columns and fretted domes, and the elegance of the designs,” wrote the Calaveras Chronicle in 1854. They described it as a place “where nature exhibits how far her handiwork transcends the most exquisite productions of man.”

In an act of, what Kilbreath calls, “historical vandalism,” those first visitors were encouraged to etch their names onto the cavern walls. The litany of signatures — carved into the rock with a steel nail, some crude, some elegant — may appall us today, but it’s one of the reasons California Cavern is now considered a state landmark.

On rare occasions modern visitors have found the names of distant relatives marked on these rocks, says Kilbreath.

One of the most notable features of California Cavern are the underground lakes. These foreboding pools of dark water fall away into the blackness. But when you hold a light to them, the water is revealed to be crystal clear. During the flood season, unless you hear the bubbles softly rising, it’s easy to step straight into the water without even realizing.

When deemed safe, California Cavern opens the lakes to tour groups, who raft or swim across them. While Kilbreath says it’s “pretty neat” to be able to say you swam in an underground lake, it’s also “a little creepy knowing there's 80 feet of pitch black water below you.”

When the caverns first opened, writers like Mark Twain and Bret Harte paid a visit. John Muir visited in 1876, and later wrote how the caverns were “all a-glitter like a glacier cave with icicle-like stalactites and stalagmites combined in forms of indescribable beauty.”

Above ground, the small town of Cave City that sprung up around the cave mouth in the 1850s began to develop an unusually close relationship with the underground world that stretched below them. First, the townspeople built a hotel at the entrance. Then the town itself began to spill down into the caverns.

They built a saloon where prospectors and visitors alike could swig their whiskey under sheets of solid rock. (“The bad joke for that: It's the cavern tavern,” says Andrew.)

Deeper inside, in a domed vault they called “the Bishop’s Palace,” the people of Cave City built their church, complete with an organ. Stepping into this hushed space, it’s hard not to imagine how angelic those services must have sounded.

The Bishop’s Palace was named for a pillar of rock the people of Cave City thought resembled a Roman Catholic bishop wearing robes — illustrating how 80 feet underground, the human eye seeks out familiar shapes and patterns like it does when faced with clouds.

Rock formations known as 'flowstones' look like frozen waterfalls — they're created by mineral-rich water dripping down the cave walls and depositing calcite. Pillars of rock looks like human figures, and elsewhere formations look like jellyfish, dinosaurs, even monstrous faces.

“If you do have a good imagination you can spend hours down here staring up at the ceiling,” says Kilbreath.

Today, our subterranean sightseeing is enabled by the colorful artificial lighting that bathes California Cavern. It’s the kind of illumination that, if it hadn’t been for Captain Taylor’s curiosity, would never have been brought down here.

The idea that the cave’s beauty was previously “shrouded in darkness all the time” is something that particularly strikes Kilbreath each time he visits the caverns.