On October 27, 1981, Mammoth Cave National Park joined the ranks of renowned places like Australia's Great Barrier Reef, Egypt's Pyramids of Giza, Nepal's Kathmandu Valley, and India's Taj Mahal Historic Park. The United Nations Educational Scientific and Cultural Organization (UNESCO) designated Mammoth Cave National Park as a World Heritage Site for its exceptional natural features, its habitat for threatened and endangered species, and its association with events and persons of world historic and archeological significance.

Mammoth Cave National Park, unlike many sites on the list, is known for its natural heritage as well as its cultural heritage. Mammoth Cave is the most extensive cave system in the world, with more than 345 surveyed miles of cave passageways. Pre-Columbian Native Americans explored further into Mammoth Cave than any other cave in the world -- over three miles distant from any probable point of entry.