Date: July 3, 1964

On this day, Natural Bridge Caverns, the largest known cavern in Texas, was opened to the public. The cavern was discovered on March 27, 1960, by four spelunkers who were students at St. Mary's University in San Antonio. It is located off Farm Road 1863 in the hill country of Comal County midway between New Braunfels and San Antonio. The name was derived from a sixty-foot natural limestone slab bridge that spanned the amphitheater setting of the cavern's entrance. The developed portion of the cave, furnished with a half mile of paved trails and illuminated by 35,000 watts of indirect lighting, extends to as much as 260 feet below ground level. Natural Bridge Caverns became a registered United States natural landmark in 1971.