Final answer:
The largest known cave system in the world is Mammoth Cave National Park, located in Kentucky, with over 400 miles of mapped passages.
Step-by-step explanation:
The world's largest known cave system is called Mammoth Cave National Park, located in the state of Kentucky, USA. This extensive network of caves spans over 400 miles (640 kilometers) and is recognized by the Guinness World Records as the longest cave system. While other caves such as the Chauvet Cave in France, Lascaux Cave, and the Sulawesi Cave in Indonesia are notable for prehistoric cave paintings and are significant archaeological sites, Mammoth Cave holds the record for its intricate and voluminous passageways. Not only a UNESCO World Heritage Site, it is also a major tourist and scientific attraction, contributing to our understanding of geological and biological processes spanning millions of years.