Grand Caverns

Grand Caverns, formerly known as Weyer's Cave, is located in the central Shenandoah Valley in the town of Grottoes, Virginia, United States. A limestone cavern, it claims the distinction of being America's oldest show cave, in operation since 1806. In 1973, the National Park Service designated the cave a National Natural Landmark in recognition of its shield formations and other features, such as flowstone, stalactites, and stalagmites.

Cave data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).