California’s unique geography of ancient sea beds and tectonic plate uplifts has resulted in nearly 20 named caves, from Lava Beds National Monument up north to Sunny Jim’s down south. From calcite to limestone, great chambers to lava tubes, caves’ visual diversity intrigues the eyes. And when it’s hot here in the Valley, the caves are a cool 55-65 degrees, making for a great escape.

“Spelunk” means the exploration of caves. Which is perfect, given the highest concentration of caverns are right nearby, creating spelunking opportunities ranging from an easy amble to wiggle-your-way-through-narrow-tubes adventures. Black Chasm Cavern (Volcano), California Caverns (Mountain Ranch) and Moaning Cavern (Vallecito) are managed by Cave & Mine Adventures (CaveAndMineAdventures.com). There’s also Mercer Caverns (Murphys, MercerCaverns.com), and Natural Bridges (Vallecito, GoCalaveras.com/Natutral-bridges-hike).

For my first local cave, I chose Moaning Cavern, attracted by the variety of activities offered. Just off Parrots Ferry Road, between Angels Camp and Murphys, the 165-foot deep main cave (tall enough to hold the Statue of Liberty) earned its name from Swiss-cheese like holes in the rippled stone. When water drips into them, they moan – so loudly, that it’s audible from the outside.

Miwok Indians believed that it was a stone giant attracting victims by imitating a small child crying. When gold prospectors discovered the cave in the 1850s, they found a mound of debris that contained animal and ancient human skeletons. You’ll see a portion of this fossilized bone pile on the Walking Tour.

Moaning Cavern opened for tours in 1922. Initially visitors were lowered by winch and rope in half a wine barrel with only a candle! Subsequently, what was considered an architectural marvel at the time was installed: a 100-foot spiral staircase taken from a World War I battle ship and arc-welded without a single nut or bolt, the first such project west of the Rockies. You’ll descend this 144-step case that spirals 7.5 times.

There are three ways to “do” Moaning Cavern. Most folks take the one-hour Walking Tour. After an introduction to the cave’s history, escorted by our guide Fred Allen, we were swallowed by a narrow throat of stone, descending wooden steps to the main chamber. There you exit onto a platform that overlooks the cave.

If you’re lucky, you’ll get to watch brave visitors rappel into the cave, suspended over 100 feet to descend in a free descent. In winter and spring (Moaning Cavern is open year ‘round), they have to pass through a waterfall. While no cameras are allowed when rappelling, each person I watched had a GoPro® on their helmets. Anyone over age 12, 100 pounds and four feet tall may do the Rappel.

As we twined our way down the staircase, Fred regaled us with stories, pointing out formations with his high powered flashlight. Cave bacon, a “chocolate waterfall”, the half-million year old igloo, flowstone – eons of water has carved the calcite into extraordinary shapes.

When he spotlighted “Godzilla’s Nostril”, Fred explained how it’s part of the Adventure Trip. For hard core wrigglers, this tour is for you. Staff guide you on a three-hour prowl through a labyrinth of passages, some just shoulder-width. There are multiple exit passages for people who are simply too wide or decide that slithering through narrow tubes isn’t for them. Fred said there are no bugs, but advises wearing grubby clothes – you’re guaranteed to come out dirty.

Then Fred flipped off the lights. The thick darkness and muffling silence that engulfs you makes you realize that for those who fell in, nobody would hear them scream.

Then it’s back up to fresh air and more things to do.

Just up the slope from the shop are the Twin Zip Lines – 1500 feet of wires down which harnessed guests race at speeds up to 35mph. Friendly staffers secure you, and then, zoom! It’s a blast! Stick out your arms if you want to twirl around a bit in your harness.

If you still have energy, try the 32-foot high Climbing Tower with 10 different routes. And what’s a trip up to the Gold Country without gemstone mining? You can buy a bag of “rough” and test your hand at sluice mining to find treasure. Fun times can be had by all!

Wear comfortable flat shoes. Flash photography is permitted. Go earlier in the day (Sunday mornings are great); this popular attraction gets busy. Group reservations are welcome (866.762.2837).