Science Fair Project Encyclopedia
Natural Bridge Caverns
Natural Bridge Caverns are the largest known caverns in the state of Texas. The name was derived from the 20 m (sixty-foot) natural limestone slab bridge that spans the amphitheater setting of the cavern's entrance. The span was left suspended when a sinkhole collapsed below it.
The caverns are located near the city of New Braunfels, Texas in the Texas Hill Country. The caverns feature several unique speleothems and other geological formations. The temperature inside the cave is 21 degrees Celsius (70°F) year-round.
The caverns are still very active and growing. Water flows and drips constantly throughout, causing the formations to retain a waxy luster that can be seen in few caverns.
The caverns were discovered on March 27, 1960, by four students from St. Mary's University in nearby San Antonio. During excavation of the entrance trail, arrowheads and spearheads dating from 5,000 B.C. were found. Also, just inside the entrance, jawbones of a species of grizzly bear that became extinct over 8,000 years ago were discovered.
Natural Bridge Caverns became a registered United States natural landmark in 1971. The site is tourist-oriented and suitable for children.
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