Hidden beneath the rolling hills of the scenic Texas Hill Country a few miles northeast of San Antonio is Natural Bridge Caverns -- a wonderland of living stone discovered by four St. Mary's University students in 1960. The four were originally drawn to the site by its namesake rock bridge, a 60-foot span of limestone rock spanning a cavernous sinkhole -- tell-tale clues to the existence of an enormous underground cave formed by a subterranean river.

Viewing the spectacular innards of the caverns today, it is easy to imagine the thrill felt by the four spelunkers as they gazed for the first time on such natural wonders as: "The King's Throne," with its elaborate, calcified canopy and curtains hovering over massive armrests and footstool fit for a king; the immense, lace-like "Watchtower," and the feathery leafed ceiling of "Sherwood Forest." These formations, called speleothems, were created over thousands of years by droplets of rainwater picking up carbon dioxide in the soil. That created carbonic acid, which dissolved the Hill Country limestone rock and swept its minerals into the underground caverns where they became the fantastic formations seen by visitors today.

Underground Treats

The crystalline speleothems found here grow at a rate of only one cubic inch per 100 years. There are long, hollow "soda straws" extending from the ceilings, stalagmites resembling fried eggs and ribbon-like "cave bacon." Extra precautions have been taken to seal in the moisture in this wonderland of nature to ensure it remains a "living" cave. Year-round, the caverns remain just 70 degrees with a humidity of 99 percent.

For the really daring, Natural Bridge Caverns now offers the Adventure Tour. Visitors don jump suits, hiking boots and hard hats with headlamps for a chance to experience the undeveloped South Cavern, discovered in 1967 but only recently opened to the public. Those opting for the Adventure Tour brave a 4-hour expedition of climbing, rappelling and crawling through a mile-long, spectacular cavern system. You can plunge to 230 feet below the earth's surface and have the option of being lowered through the 160-foot entry shaft, like the original explorers of the South Cavern. (Health, size and age restrictions apply.)

Pan for Gemstones

A popular attraction on the premises is the Natural Bridge Mining Company Sluice, where guests pan in a trough of flowing water for gemstones in purchased bags of rough mix and are guaranteed to walk away with a handful of sparkling quartz, sapphires, rubies, amethysts, emeralds, crystals or pyrite ("fool's gold") -- and more. At least one lucky "miner" has walked away with a gemstone-quality ruby to be set in jewelry.The Visitors Center boasts an enticing gift shop, a snack bar and fascinating display cases that outline the history of the Caverns, and outside, the picnic areas and a playground of three friendly dinosaur statues welcome travelers.

Above or below the ground, Natural Bridge Caverns will be an adventure you'll long remember.

Natural Bridge Caverns
26495 Natural Bridge Caverns Road
(Off IH-35 between
San Antonio & New Braunfels)
210-651-6101
Daily, 9 a.m. to 6 p.m.
North Cavern Tour
75-minute tours every 30 minutes
13+ yrs. -- $12
4 to 12 yrs. -- $7
65+ yrs. -- $10
Adventure Tour
Reservations Required
Shaft entrance -- $100
Walk-in -- $75