Day Trips

Natural Bridge Caverns, Texas' largest underground gallery of shapes, colors, and geological formations, just got bigger. This year, the New Braunfels-area cave opened a new tour to a second underground chamber just as spectacular as the original cave.

Called the Illuminations Tour because of the dramatic effects produced by minimal lighting, the spelunking goes to a section known as the Hidden Passages. "This portion of the cave never had a natural entrance," says Brian Vauter, head geologist at the caverns and sometimes tour guide. "[The new section] gives me a real sense of exploration and makes me wonder what might be on the other side of the rock walls."

Four college students from St. Mary's University in San Antonio discovered the first cave entrance under a 60-foot-long limestone bridge in 1960. Over the years, Natural Bridge Caverns has become one of the premier show caves in the country. The collection of cave bacon, rock drapery, fried eggs, soda straws, and other colorful formations is one of the most unusual in North America. Not only are the number of formations on the three-quarter-mile original tour incredible, but such variety of natural rock sculpture can be found nowhere else.

Since the opening of the main cave to the public, experts had suspected a second room might exist under the hill to the south of the main entrance. It took five tries before their drill bit broke through to empty space 160 feet below the surface. When the first explorer was lowered through a narrow shaft into a corner of the underground room, he wasn't disappointed by the enormity of what he saw.

The first room discovered opened into an underground amphitheatre that tilted into the darkness. In the glow of a flashlight, the rock looked like mounds of melted wax wet from water dripping through the cracks in the ceiling. Stalactites hung from the ceiling, and stalagmites grew from the floor of the open space that's larger than a football field.

Thirty years after it was discovered, the Hidden Passages section was opened to adventure tours for cavers who didn't mind entering through the shaft and crawling through the mud. It wasn't until 2002 that the walkway was begun, and the cavern opened to occasional tours using handheld flashlights.

When guests walk through the double doors that seal the damp underground world from the dry Texas landscape above, they walk down 185 steps into a world that is a constant 70 degrees and 99% humidity. Under the thick limestone roof, there is no natural light, Vauter says.

When the lights do come on, the rock formations radiate in a rainbow of pinks, reds, yellows, and oranges. The inky darkness on the edge of the light only serves to accent the delicate forms and massive shapes. "We don't light up everything," Vauter says. "We just use it to highlight the formations." In the entire cave, he estimates they use only about 150 lightbulbs.

The tour leads down about one-third of a mile to the Cathedral Room, where a massive pipe-organ rock formation flows over the side of the wall. This is a chamber that had seldom been opened to tours until now. While guests rest on benches and admire the natural beauty, Vauter describes what they are seeing.

This is still very much a living cave. In fact, a rock formation began growing on the steel handrail along the path. As slightly acidic rainwater percolates through the cracks and pores of the limestone, it gradually dissolves the rock and enlarges the openings. Each drip of water deposits trace amounts of minerals to build new rocks gradually.

Natural Bridge Caverns is 12 miles south of New Braunfels and eight miles west of I-35. Tours leave the visitor center every 30 minutes or so between 9am and 4pm, with extended hours during the summer months. Each tour lasts about 70 minutes and requires moderately strenuous walking on steep, wet surfaces. For more information, call 210/651-6101 or go to www.naturalbridgecaverns.com.

873rd in a series. Day Trips, Vol. 2, a book of "Day Trips" 101-200, is available for $8.95, plus $3.05 for shipping, handling, and tax. Mail to: Day Trips, PO Box 33284, South Austin, TX 78704.