Mammoth Cave National Park is about a ninety minute drive south of Louisville and it wasn't a big deal getting there and back, so we signed up for both a morning and afternoon tour to see different parts of the cave. The morning tour focused on history and went through areas of the cave that were explored starting thousands of years ago. Apparently, Native Americans explored about 12 miles of the cave with torches thousands of years ago, which I think would be pretty scary - if you're 12 miles from the entrance and your torch goes out I expect it would be very challenging to get back to the entrance. Fortunately for us, the trails have since been paved and lit with electricity so it was a pretty easy saunter for most of this tour.
This is the 'original' entrance that has been open for thousands of years
Our little handheld 'adventure' camera did really really well with pictures in the dark; more came out than didn't. Mammoth is a 'dry' cave (meaning water is not still dripping through most of it) so while it is the biggest in the world by a large margin, it is somewhat less decorative than a wet cave that would have more stalagmites and so forth.
The clear path, lighting, and handrails made the cave feel almost like a fake cave, and disguised how far in and down we were - we went about a mile laterally underground and about 350 feet below the surface with a bunch of twists and turns. Most parts were very open but in some we had to duck or contort to get through openings - they preferred to make the path fit the cave and not the other way round.
In some places the roof had been marked by candle or lantern smoke from 19th century explorers.
Fat Man's Misery was narrower than some other areas and the walls have been smoothed and polished by the passage of millions of people (literally).
Smoke from 1855
Many passages were...Mammoth...in proportions.
The "new" entrance was blasted by dynamite in the 20's or 30's.
Wooden stairs handled this entrance until the 60's but then they were so rickety they needed to be replaced and this entrance was closed for a while while they figured out how to best replace them. According to the rangers, they went through a number of contractors that said it couldn't be done before hiring a company that generally fabricated submarines and knew a thing or two about stairs in confined spaces. They weren't allowed to change the cave so the stairs spiral downward in elaborate and unusual ways.
Sometimes the stairs crossed through more open areas (this one has a BIG drop underneath it).
At a few points in both tours the rangers would stop and give a talk on the history and geology of what we were seeing. Sometimes there were benches for people to sit on at these points, especially if the rangers planned to talk for a while. Ana has a new record for distance below ground she has knitted of about 350 feet. She was only knitting when seated, to keep hands free for railings, etc, the rest of the time.
Some walls had lichens on them but I'm really not sure how they survive down there.
We did see one area with dripstone formations that was pretty neat.
All in all I would recommend Mammoth Cave's tours as a relatively easy outing with good education about caves and geology. We may go back for more tours and maybe the really difficult spelunking tour when they only take fit adults of less than a certain size (too big and you'd get stuck in a passage) sometime before we leave the area. We'd also be interested to see some of the other notable cave national parks.
See Mom? We didn't die.