cavern. The full-time development crew included Mrs. Wuest-Heidemann, Mr. Heidemann, Jack Burch, Orion Knox, and Reggie Wuest (Mrs. Wuest-Heidemann's son). Development on the cavern began in 1963 and work on lights and trails continued until opening day, July 3, 1964. The cavern has been opened ever since and is still owned and operated by family members. Natural Bridge Caverns became a registered United States National Natural Landmark in 1971. During excavation of the entrance trail, a human tooth, arrowheads, and spearheads dating from 5,000 BC were found. Also, just inside the entrance, a jawbone and femur from an extinct species of black bear were discovered. This leads many to believe that the uppermost areas of the cavern were used as a shelter by early peoples and animals at some point. An archaeological dig was recently done under the natural bridge. Archaeologists recovered arrowheads and other tools which further indicate the presence of early peoples at some point in history. Further exploration In 1967, speculation on a southern extent to the North Cavern was confirmed when test drilling indicated the presence of a large void approximately 90 feet beneath the surface. A camera was sent down the narrow shaft and photographs revealed a large chamber filled with formations. This original shaft was reamed out to 22 inches and three men were lowered into the ground. They discovered a large breakdown chamber and numerous formations. The first three men to enter this room were Jack Burch, Reggie Wuest, and Myles Kuykendall. By combining the first two letters of each man's first name, they arrived at JAREMY, and thus this newly discovered room was called the Jaremy Room. Further investigation near the bottom of the Jaremy Room revealed a strong likelihood that another passage existed beyond a pile of rocks and boulders. In 1968 the drillers were once again brought out to the property and another exploratory shaft was sunk into the ground. This shaft also penetrated a large void approximately 150 feet below ground. As before, the initial shaft was enlarged and people dropped down into the unknown. Explorations revealed another half-mile of cavern extending to the south. This then became known as the South Cavern. Recent exploration Exploration continues to date. During the summer of 2005, several hundred feet were added to the current surveyed length of the cave. It is believed that as much as another mile could be added