Natural Bridge Caverns are the largest known commercial cavern

Cave

A cave or cavern is a natural underground space large enough for a human to enter. The term applies to natural cavities some part of which is in total darkness. The word cave also includes smaller spaces like rock shelters, sea caves, and grottos.Speleology is the science of exploration and study...

s in the state of Texas

Texas

Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

.The name was derived from the 20 m (65 foot) natural limestone

Limestone

Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

 slab bridge that spans the amphitheater setting of the cavern's entrance. The span was left suspended when a sinkhole

Sinkhole

A sinkhole, also known as a sink, shake hole, swallow hole, swallet, doline or cenote, is a natural depression or hole in the Earth's surface caused by karst processes — the chemical dissolution of carbonate rocks or suffosion processes for example in sandstone...

 collapsed below it.

The caverns are located near the city of New Braunfels, Texas

New Braunfels, Texas

New Braunfels is a city in Comal and Guadalupe counties in the U.S. state of Texas that is a principal city of the metropolitan area. Braunfels means "brown rock" in German; the city is named for Braunfels, in Germany. The city's population was 57,740 as of the 2010 census, up 58% from the 2000...

 in the Texas Hill Country

Texas Hill Country

The Texas Hill Country is a vernacular term applied to a region of Central Texas featuring tall rugged hills consisting of thin layers of soil atop limestone or granite. It also includes the Llano Uplift and the second largest granite monadnock in the United States, Enchanted Rock, which is located...

 next to the Natural Bridge Wildlife Ranch

Natural Bridge Wildlife Ranch

Natural Bridge Wildlife Ranch is a safari park on the northern outskirts of San Antonio, near New Braunfels, Texas. The Natural Bridge Caverns is not affiliated but is located nearby...

, a drive-through wildlife safari park

Safari park

A safari park, sometimes known as a wildlife park, is a zoo-like commercial tourist attraction where visitors can drive in their own vehicles or ride in vehicles provided by the facility to observe freely roaming animals...

. The caverns feature several unique speleothem

Speleothem

A speleothem , commonly known as a cave formation, is a secondary mineral deposit formed in a cave. Speleothems are typically formed in limestone or dolostone solutional caves.-Origin and composition:...

s and other geological

Geology

Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...

 formations.