The deposits of calcite glimmered like diamonds. It was 1859, and at the bottom of a rocky valley not far from the already famous Mammoth Cave, a slave from a local estate had stumbled upon a mysterious opening in the rock. Lowered into it on a rope, he became the first person to admire the sparkling walls of what would come to be known as Historic Diamond Caverns.
Today, the guides and geological experts of Historic Diamond Caverns lead tourists into halls of calcite-laden formations whose origins go back some 10 million years. Narrow corridors, carved out of the limestone eons ago by underground streams, open to cathedral-like chambers adorned in stalactites and stalagmites, draperies, and pipe organs that represent millions of years of slowly accumulating mineral deposits. Strategically placed lighting reveals the deposits' diamond-like shimmer as well as creatures such as salamanders, insects, and crayfish, which are adapted for life without sunlight or adequate cell-phone reception. Located close to Mammoth Cave National Park, a World Heritage Site and International Biosphere Reserve, Historic Diamond Caverns remains at a comfortable 58 degrees throughout the year.