How to explore the state’s caves, caverns, and fascinating geology.
6 Ways To See Texas Below the Surface

This National Natural Landmark is highly regarded as one of the country’s most beautiful caves. This limestone cave is full of speleothems, or calcite-based cave formations. You’re probably familiar with stalagmites and stalactites, which grow from a cave’s floors and ceilings respectively, but there are dozens of other types of formations you can find in caves, including the Caverns of Sonora. The helictites here are particularly striking: these protrude out of walls at odd angles, looking like alien crystal plants affixed to the wall. The Caverns of Sonora include a series of show caves, which means they have been adapted for visitors with stairways, lights, and walkways that allow you to see everything the cave has in store. Tours for adults and children are available daily, and can be booked on the Caverns of Sonora website. 

Don’t be scared—there’s nothing demonic about this beautiful geological formation. The Devil’s Sinkhole is, indeed, an enormous hole in the ground, though unlike the ones you might find on paved streets, this one was naturally formed over thousands of years thanks to rainfall that eroded the limestone rock that surrounds it. This resulted in an enormous underground cistern—350 feet deep, and 300 feet wide—that has since become the home base for roughly 3 million bats. On warm nights, visitors can see these bats emerge from their enormous hole in the ground to go out and search for food, which is quite the sight. When the bats leave, a swarm of cave swallows will often swoop in to take their place belowground, in search of rest; when the bats arrive home in the morning, the birds leave. It’s a fascinating natural cycle. The best time to visit Devil’s Sinkhole is between late spring and early fall. 

Hidden beneath the rolling landscape of Texas Hill Country, this cave offers striking underground formations. Along with the stalactites and stalagmites here, you’ll find soda straws (which look like crops of straws made of crystal); cave drapery (limestone formations that look like loose curtains rippling with wind); flowstones (collections of sheetlike deposits that look, at times, like a long mane of hair emerging from a cave wall); and rimstone dams (rims of calcite extending into a pool like a very delicate staircase). While the cave has existed for thousands of years, it wasn’t discovered until the early 20th century, and its uppermost cave was actually used as a moonshine distillery during prohibition. In the 30s, the land was purchased by someone hoping to show the caves after a trio of local boys discovered its depths. The cave’s name—or lack of one—comes from a state-wide contest, during which a local boy claimed it was “too beautiful to have a name.” A newspaper article recounting the story hangs in the cave gift shop today.

What separates this Cistern from other below-ground wonders is its man-made nature: instead of flowstones and helictites, the Buffalo Bayou Park Cistern’s geography is made up of concrete columns. Built in 1926, the space was one of Houston’s first underground reservoirs. Its 87,500 square feet were used for public works, with an eight-inch-thick concrete roof supported by 221 pillars. After an irreparable leak in one of its walls forced the city to decommission the reservoir in 2007, and it lay dormant for years. Luckily, instead of demolishing it, the city decided to keep it as-is and turn it into a visitor attraction as they developed the nearby Buffalo Bayou Park. You can visit the cistern Wednesday through Sunday, on self-led or docent-guided tours. It also offers regular sound healing meditation sessions, which make use of the space’s unique acoustics.  

If you’re ever concerned with your own aging, just remember that this cave is at least 20 million years old and still looks gorgeous! The Inner Space Cavern, located about 25 miles north of Austin, is filled with striking cave formations. It was discovered by a drilling team from the Texas Highway Department in the 1960s, while they were constructing an overpass for Interstate 35. A few years after being mapped by the Texas Speleological Association, it opened to the public in 1966. Prehistoric animal remains have also been found here, including those of a baby mammoth, giant sloth and a saber-toothed tiger. During the Ice Age, experts say, there were a few big openings to the cave, through which these animals likely fell.

Today, visitors can enjoy a variety of tours of the cavern; there’s even one that focuses on its Ice Age history. Other activities on site include gemstone panning and a zipline ride.

The 6,300-acre Kickapoo Cavern State Park includes 20 caves, Kickapoo Cavern and Stuart Bat Cave. In the spring and summer, Stuart Bat Cave is home to over a million Mexican free-tailed bats, who emerge each evening to feed. It’s about a hundred feet deep and a thousand feet wide; it has been known to locals since at least the 19th century, though it’s often overshadowed, cave-wise, by nearby Kickapoo Cavern. Arrive in the evening to watch the bats take flight against the vast Texas sky.