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Natural Bridge Caverns: A Geologic Wonder in San Antonio

A short drive north of San Antonio, Texas, the Natural Bridge Caverns are an awe-inspiring geologic wonder, perfect for adventure-seekers of all ages.

Discovered on March 27, 1960, by four college students from nearby St. Mary's University, these caverns are named for the massive, 60-foot limestone bridge spanning their entrance. The bridge was created when a sinkhole formed around it.

Limestone bridge
Limestone bridge

The caverns date back to the early Cretaceous Period, 66 to 145 million years ago. Artifacts dating to 5,000 B.C. and human remains as old as 8,000 years have been found here.

After learning about the presence of the cave, Clara Wuest, the landowner, worked with one of the students and others to develop and open the cave to the public on July 3, 1964.

Natural Bridge Caverns has remained in the family ever since, and in 1971, it was named a U.S. National Natural Landmark. Today, it's the largest commercially-operated cave in Texas.

Visitors can embark on guided tours to explore vast underground chambers with stunning formations like stalactites, stalagmites, and flowstones. And that's precisely what I did on my way home from celebrating the Holidays on Houston Street in San Antonio.

Cavern Tours

Natural Bridge Caverns tickets
Natural Bridge Caverns tickets

Before I take you below ground to see some of the cave system's most spectacular formations, let's review the cavern tour options.

Discovery Tour: This guided tour takes you into the first cave discovered in 1960. The tour lasts about 60 minutes, reaches a maximum depth of 180 feet, and covers a distance of 0.75 miles.

Hidden Wonders Tour: Launched in spring 2023, this tour introduces visitors to a new cave. The tour is about 75 minutes long, reaches a maximum depth of 160 feet, and requires 0.5 miles of walking.

Combo Tours: The combo tour ticket allows you to do both the Discovery and Hidden Wonders tours on the same day, with a break in between.

Same-day adult entry fees are $31 for the Discovery Tour and $32.75 for the Hidden Wonders Tour; the Cavern Combo Tour is $53.50. And you can save a few dollars by buying tickets online in advance.

Adventure Tours: If you want to go off-the-beaten-track, are comfortable in tight spaces, and don't mind getting dirty, Natural Bridge Caverns offers two more adventurous cave tours. Ticket prices are higher, but so too are the risks.

The 2 to 3-hour St. Mary's Adventure Tour for $129.99 takes you into a “wild” portion of the Discovery Tour cave, where you'll sometimes use ropes.

The 3.5 to 4-hour Discovery Adventure Tour for $169.99 recreates portions of the initial cave explorers' expedition. You can do both tours for $249.99 for a full day of adventure. A box lunch is included.

The caves' temperature is consistent at 70 F (21 C) with 99% relative humidity. Wear comfortable shoes with some grip, like trail running sneakers or hiking shoes. Avoid flip-flops, sandals, or anything that may cause you to slip on wet surfaces.

To make the most of my visit with Kel, we chose the Combo Tour; we did the Discovery Tour first, followed by Hidden Wonders.

Natural Bridge Caverns Discovery Tour

Discovery Cave entrance
Discovery Cave entrance

A few minutes before our 2 p.m. start time, we met our tour guide, Ryleigh, who reviewed the cavern rules.

They include the importance of staying on the walking trail and not touching any rock formations, many of which have been forming for thousands of years. There are no restrooms once you descend into the caves; no food, drinks (other than bottled water), or smoking is allowed.

We descended a paved path beneath the limestone bridge and into the Discovery Cave. The first noteworthy sign we saw was labeled The Bear Pit, where 8,000-year-old black bear remains were found at a depth of 45 feet.

Fifteen minutes into the cavern tour, we were walking past a narrow and low-to-the-ground passageway that marked the entrance to the cave. Crouching down and peering into it, I couldn't imagine squirming through the rocky crevice with only the light of a headlamp to guide me.

Pluto's Anteroom

The first large chamber we entered is named Pluto's Anteroom (dept: 108 feet). Here, we paused so Ryleigh could share more facts about what we were seeing. There were some stone benches for those who preferred to sit.

Pluto's Anteroom on the Discovery Tour
Pluto's Anteroom

The most fascinating feature she shared was the black markings on the ceiling, which resulted from a bat colony that once lived in the cave. The discoloration results from the bats' bodies rubbing against the ceiling for who knows how many years.

Bat markings on the chamber ceiling at Natural Bridge Caverns
Bat markings on the cave ceiling

From Pluto's Anteroom, we continued to descend into the cave. An impressive grouping of stalactites and stalagmites named Sherwood Forest is seen at a depth of 180 feet.

The delicateness of many of these formations, combined with the knowledge that they've been forming over thousands, perhaps tens of thousands of years, is truly astounding.

Sherwood Forest stalactites and stalagmites
Sherwood Forest stalactites and stalagmites

We left Sherwood Forest to walk above Purgatory Creek. At 211 feet, it's the deepest point in the cave. It was also one of my favorite rooms on the Discovery Tour.

Once I reached the opposite end from which we entered, I turned back to look again in appreciation at the otherworldliness of the environment.

Purgatory Creek
Purgatory Creek

It also occurred to me that building these pathways in the caves and installing the lighting must have been a slow and methodical process. I'm sure every effort was made to avoid damaging the delicate formations and disturbing the ancient mud.

Castle of the White Giants

The next big chamber we entered, named Castle of the White Giants (dept: 150 feet), featured shallow running water that formed pretty little pools on the cave floor.

Watchtower, the tallest column in Natural Bridge Caverns at 50 feet, rose from a larger pool of crystal-clear water.

The Watchtower as seen on the Discovery Tour at Natural Bridge Caverns in San Antonio, TX
The Watchtower
King's Throne
King's Throne

I tried to choose photos I felt would show up best, whether you're reading this on a phone, tablet, or laptop. However, none hold a candle to what it's like to walk through the cave chambers firsthand.

Kel, who'd driven by Natural Bridge Caverns countless times throughout her life in Texas, was equally impressed. She'd been the one to suggest we check them out.

Kel at Natural Bridge Caverns
Kel on the Discovery Tour

Emerald Lake glistened as we walked past it. Unlike the many beautiful bodies of water I've encountered from Thailand to the Bahamas, there would be no swimming here.

Emerald Lake in Natural Bridge Caverns
Emerald Lake

Fun fact: the largest underground lake in North America is called The Lost Sea at Craighead Caverns in Tennessee. It's 800 feet long and 220 feet wide; it's so large visitors board glass-bottom boats on their cave tour.

Hall of the Mountain King

At a depth of 135 feet, the Hall of the Mountain King is the largest chamber in the cave and our way out. The chamber was illuminated after we had had a minute to take in the scenery from below with the lights out up top.

A long and winding path leads visitors up and out of the deepest areas of the Discovery Cave. Given the 99% relative humidity, walking this section will make you sweat.

This steeper section of the trail has handrails and a special surface to provide good traction.

Hall of the Mountain King
Hall of the Mountain King
Ascending the Hall of the Mountain King at the end of the Discovery Tour.
Ascending the Hall of the Mountain King

Throughout the Discovery Cave tour, you're getting up close (within arm's reach) to the rock formations. This felt especially true on the walk up the cavern's biggest chamber.

At the top, there's a water fountain where you can take a sip of the cave water. It's at this point that the tour concludes. Guests can exit the remainder of their way at their own pace. After tipping Ryleigh for a job well done, we emerged into the late afternoon sunlight after an hour below ground.

Watch the video below to learn more about the history of the caverns from two of the four college students who found it in 1960.

We had about a 45-minute break between the end of the 2 p.m. Discovery Tour and the start of the 4 p.m. Hidden Wonders Tour, the newest to be offered at Natural Bridge Caverns.

We used the free time to grab snacks at the concession stand opposite the admission counter, check out the gift shop, and use the restrooms.

Hidden Worlds Tour

At 4 p.m., we met a new guide for our second foray into the underground world beneath San Antonio.

There were about double the number of visitors for this tour, including many little kids and at least one baby. No strollers are allowed, so any kids need to be able to walk on their own or be carried.

The experience began with reviewing the safety tips and introducing how the cave was discovered.

In short, several small exploratory holes were drilled in the same area as the Discovery Tour, and the fourth one suggested a new and massive underground chamber.

Well Shaft #4 was widened to a diameter of four feet, and a spelunker attached to a winch was slowly lowered through it. The rest is history. Our guide pointed out the shaft in the cave's ceiling once we were underground.

Lecture during the Hidden Wonders cave tour
Hidden Wonders tour

The multi-million-dollar development of this particular cavern began in 2017, and it started seeing visitors in May 2023.

Unlike the Discovery Tour, which was accessible from a natural opening in the ground, the Hidden Wonders cave had been entirely sealed off throughout human history.

Whereas the Discovery Cave begins with tight passages and small rooms, with Hidden Wonders, you'll be immediately presented with an enormous underground chamber.

Hidden Wonders Tour cave entrance
Entering the Hidden Wonders cave
Rock formations
Rock formations

A staircase with handrails allows guests to descend safely, taking in the captivating rock formations. Guests on the Hidden Wonders Tour reach a maximum depth of 160 feet.

The Ballroom

Near the cave's end is a 5,700-square-food dome chamber dubbed The Ballroom. This unique space now serves as an event space.

Underground event space at Natural Bridge Caverns
Special events space

Box Canyon

Box Canyon is another immense space at the far end of The Ballroom. Visitors are treated to a state-of-the-art music and light show before they exit the cavern.

Chamber used for a music and light show during the Hidden Wonders tour.
Box Canyon

Belt Assisted Transport

Speaking of exits, the folks at Natural Bridge Caverns spared no expense when they developed the world's first Belt Assisted Transport (B.A.T.) out of a cave.

The 700-foot-long conveyor belt rises at a sufficient speed and incline to get you safely out after a few minutes.

That said, guests more comfortable walking out of the tunnel are invited to do so. Handrails and bench seating are available at several points along the path.

Kel on the Belt Assisted Transport as we exit the Hidden Wonders cave
Kel on the Belt Assisted Transport as we exit the Hidden Wonders cave.

The highlight of the Hidden Wonders tour was the initial experience of walking down the stairs in the first chamber.

Overall, I'm glad we gave Natural Bridge Caverns an entire afternoon so we could do both the Discovery and Hidden Wonders tours.

If you're short on time or only want to choose one, I'd recommend the Discovery Tour, as I felt like there were more unique formations to see in that cave.

Surface Attractions

Zip Rails and Ropes Course
Zip Rails and Ropes Course

The activities at Natural Bridge Caverns may have begun with a cave tour, but they've since expanded to include many above-ground experiences.

Chief among these is the 60-foot high Zip Rails and Ropes Course, one of the most extensive setups I've seen in person. The rope course I recently navigated while ziplining in Tampa Bay is dwarfed by comparison.

A 5,000-square-foot maze and the chance to mine for gems and fossils are a few of the attractions aimed at kids.

Since we visited in December, we also saw the Christmas decorations displayed at Natural Bridge Caverns for the holidays. These included a 30-foot tree, a 1/3-mile trail of lights, campfires and s'mores, live music, and ice skating for kids.

Big Daddy's restaurant at Natural Bridge Caverns
Big Daddy's Sweets

Regardless of what time of year you visit Natural Bridge Caverns, you'll find sweets like fudge and Blue Bell ice cream, barbecue, and beer at Big Daddy's. If we hadn't been full from our brunch at Market Square in downtown San Antonio, I would've tried the brisket.

Final Thoughts

As our day at Natural Bridge Caverns drew to a close, I couldn't help but feel a sense of awe and appreciation. These caverns are not only a testament to the natural beauty in the state of Texas but also rank among its best attractions.

Exploring these underground marvels, formed millions of years ago, far beneath the Earth's surface, is humbling and exhilarating. It's a journey that connects us to the past in a profound way, reminding us of the incredible forces that shape our planet.

Whether you're an adventure seeker, a cave enthusiast, or simply someone who appreciates the wonders of the natural world, Natural Bridge Caverns is a remarkable destination worth your time.

For more information and to purchase tickets, visit the Natural Bridge Caverns website.


I received complimentary Combo Tour tickets in collaboration with Natural Bridge Caverns.

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