51. Story of Mammoth Cave

Mammoth Cave is the name of a national park in south-central Kentucky, USA, as well as the longest cave system known in the world. It has over 285 miles of surveyed cave passageways within the park, and contains a rich diversity of plant and animal life, some of which are unique to the cave environment. It is also a **UNESCO World Heritage Site** and an International Biosphere Reserve. You can visit the park and take guided tours of the cave, or enjoy other activities like camping, hiking, biking, horseback riding, fishing, and boating.