MAMMOTH CAVE: The Longest Cave in the World Kentucky, maybe now one of the most famous cities in the world. Because, one of the biggest fried chicken factories in this area is Kentucky Fried Chicken (KFC).

This cave truly deserves its name, it is the longest known cave system in the world. There are more than 400 miles (643 km) of cave tunnels explored, a number that continues to grow as more and more is