SAN LUIS POTOSI, Mexico — Imagine if you took a big bottle of Champagne, shook it up, popped the cork and let the bubbles rush all over your body. Now imagine you’re 60 feet beneath the surface and strapped into scuba gear when it happens. That is the riotous joy one experiences when floating above a geothermal spring.

I’ve discovered this while swimming past one of the six springs that feeds a little-known prehistoric lagoon in Mexico called Media Luna. Lost in its whirlpool of bubbles, I watch in awe as they tickle around my skin.

Swimming through Media Luna’s crystal-clear waters, I pass a petrified forest and cavernous subterranean corridors en route to a spot where, in the 1970s, underwater archaeologists discovered the fossilized remains of a mammoth. Its head lay on the bottom alongside hundreds of pre-Hispanic offerings deposited in this crescent-shaped oasis by the region’s ancient settlers, who used it as a center of worship.

Not only is Media Luna one of the most intriguing underwater archaeology sites in Mexico; it’s also a haven for beginner divers. Ossiel Martinez of Dive School Media Luna says famed explorer Jacques Cousteau once named this lagoon among the best spots on the planet to learn the basic techniques of cave diving. I can see why.

What I can’t understand is why I’m one of the only foreigners here. Maybe because this undersea labyrinth is nowhere near Mexico’s famed coastline.

Most tourists visit our southern neighbor for its lavish beach resorts and towering Mayan ruins. I’ve come for adventure. I’ve based myself in the long-overlooked central state of San Luis Potosi, halfway between Mexico City and Monterrey. It boasts untouched turquoise rivers, still-thriving Wixaritari and Teenek cultures, and a terrain riddled with deep sinkholes.

The region has atmospheric places to stay, like the colonial-style Hilton (rooms from $115). Three dozen more hotels are in development. Tourism officials predict an additional terminal at the international airport in the state’s namesake capital will more than double annual arrivals from 500,000 to 1.2 million once it’s finished later this year.

My journey through this burgeoning adventure travel hub began, in earnest, two days ago in a totally different landscape: the vast wilds of the Wirikuta desert. I hiked five hours from the small colonial town of San Antonio de Coronados, past a peyote-riddled scrubland and up to a hilltop sanctuary known as Ameyaltonal, held sacred by the local Wixaritari community. When I arrived, a shaman cleansed my body with smoke and aromatic herbs in a ceremony where we honored the four cardinal directions, the earth below and the sky above.

I also took a harrowing ride on the roof of a 1961 Jeep Willys high into the Sierra de Catorce mountain range to visit the once-glorious 18th-century silver mining outpost of Real de Catorce. This former ghost town has been repopulated in recent decades and revitalized for the tourist industry, drawn to its crumbling colonial churches and charming cobbled streets.

Now, I’ve traded the arid high plains of the state’s western corridors for the subtropical forests and sinkholes of the Zona Media, home to the Media Luna lagoon.

I’m traveling with Miguel Galarraga, one of the founders of Corazon de Xoconostle Tours, a new agency that’s pioneering adventures across San Luis Potosi.

A former economist, Galarraga got into tourism as a way to share his love of climbing. So perhaps it was only a matter of time before we’d find ourselves peering over the edge of a 1,500-foot sinkhole known as Sotano de las Huahuas.

Hundreds of parrots, parakeets and swifts swirl around its perimeter in a tornado of squawking wings. We wait for them to finish their morning show and then take a leap of faith over the edge.

I have no rappelling experience, but Galarraga insists it isn’t necessary. Overcoming anxiety proves the biggest challenge as he and his team lower me like a swinging tea bag into a giant earthen cup.

Some 600 feet below, we reach the cave’s first chamber: a primordial world of moss-covered rocks and fanning ferns. We walk along its slippery, spongy terrain to peek into the depths of the second chamber. It’s a good two hours before we’re pulled to the top, just in time to catch the birds returning to their subterranean homes.

My final day in San Luis Potosi is spent in the tropical rainforests and river canyons of the Huasteca Potosina region. This easternmost section of the state is home to the Teenek dancers Voladores de Tamaletom, who “fly” around a pole while suspended upside down. It’s also where you’ll find a surreal sculpture garden by the late British poet Edward James. But my main objective is to take a wooden canoe into the even more surreal Tampaon River. My destination: the 345-foot Tamul Waterfall.

It takes nearly two hours of paddling to reach the base of this towering cascade. I break up the journey with stops at water holes along the edge, including one where you can swim into the pitch-black darkness of a limestone cave.

It’s hard to believe that just a few days ago I was in the middle of a sun-baked desert and amid the bubbles of a sacred spring. It’s a testament to the diversity San Luis Potosi packs into its compact borders.

Mexican tourists already know this. It’s about time the rest of us caught on.

Mark Johanson is a freelance writer.