HUGE cave...but not a lot of substance until near the end. Just a bunch of rocks and shit.

Waste of Time!! Only if it's your first cave will you like it. Anyone that has ever seen a real cave will agree with how bad Mammoth Cave is. It's just a hole in the ground no formations, waterfalls, stalagtities, etc...
After taking the first disappointing tour we were told to see formations we had to pay an additional fee for another tour that has them. It was just the last 10 minutes of a two hour tour. The rest was the same boring hole. We felt ripped off, left and stopped outside the park at Diamond Caverns. It was one of the best caves ever! Formations, pools, stalagtites & mites, and active dripping were here. Don't miss it.

eh, i found it to be a soso experience, mostly because of the facilities (which where lousy when i was there)

A natural wonder well worth a visit. I've never seen anything like it, but of course, who has? The vastness of the cave system here is incredible, no way to see it all in any short amount of time. Some of the cave trails are pretty heavily trafficked, but the spectacle is a wonder to behold just the same. Try one or two of the longer and/or "wilder" cave tours. A great family vacation spot.

Very Cool place to visit in hot summer months, as it is only around 55-56 degrees in the caverns and very refreshing to get down there out of the heat. Amazing as to how big the whole cave system actually is as well. Worth the trip to visit with the whole family and friends.