1. Mammoth Cave National Park is a U.S. National Park in central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world.

2. Mammoth Cave National Park is also recognized as a Biosphere Reserve by UNESCO because its diverse wildlife and ecosystems contribute to scientific study of conservation and sustainable development.

3. Unlike UNESCO designations, the sister-park arrangement between Mammoth Cave National Park and South China Karst World Heritage Site will be informal.

4. Mammoth Cave National Park in Kentucky has the longest known cave system in the world, stretching more than 585 kilometers.

5. To preserve their beauty and scientific value, Mammoth Cave National Park, in the southern United States, and South China Karst World Heritage Site, in southern China, are becoming sister parks.