How long is the world's longest cave system located in the United States?

💡 The Answer

• Mammoth Cave in Kentucky is the world's longest cave system, with over 426 miles mapped.
• It is part of the UNESCO World Heritage Site and a national park.
• The cave system was formed by dissolving limestone over millions of years.
• New passages are still being discovered, extending its known length.
• Its vast underground network includes rivers, pits, and ancient human artifacts.