Longer and deeper (no, this is not about sex)

 

So what's longer and deeper, then?  Spelunkers have mapped more passages and caverns in Kentucky's Mammoth Cave system.

EIGHT additional miles of Kentucky's Mammoth Cave are uncovered that extends the 10-million-year-old structure to at least 420 miles long

"Dr. Rick Toomey, the park's Cave Resource Management Specialist, said in a statement: 'The Cave Research Foundation is fundamentally the reason that Mammoth Cave is recognized as the world's longest cave. Without CRF exploration and mapping, Mammoth Cave would potentially still be a 44-mile-long cave system.' "

It's an extraordinary place.  I visited there when I was quite young, and it was a lot "smaller".