It might be a stretch to include a page on Mammoth Cave Waterfalls, but they do have a little historical significance even though they may be hard to photograph.
The main reason why I'm including a page on the waterfalls of Mammoth Cave is primarily due to the historical use of the weeping waterfall at the mouth of its historic entrance. According to our tour guide, water that was collected from the weeping waterfall at the entrance was brought into the cave to mine for saltpeter. Saltpeter was used for gunpowder, which was in high demand during the Civil War. The usefulness of saltpeter diminished when its value dropped after the Civil War was over.
Further into the cave, we heard some more trickling where there was a tall drop that in hindsight beared a strong resemblance to the drop of Ruby Falls. However in this instance, the water was hardly visible and could really only be heard.
Julie and I did the historical tour to get a good overview of the cave and the parts that made it famous. There were other tours that visited other parts of the cave, but I can only speculate if there might be waterfall sights on those tours (or not). Yet with that said, it wouldn't surprise us if there were more waterfalls to see on those other tours (especially the sporty spelunking ones) because all underground rivers in this cave drain towards the nearby Green River.
One thing that impressed us was the size of the cave. In addition to large rooms and subway-like corridors, our tour of the cave took two hours! Neither of us could recall doing a public cave tour that took this long, and if we couple that with the fact that there were also alternate cave tours of similar duration visiting other parts of the cave, it's no wonder how this cave got its name.
We felt it was definitely worth the $12 per person tour fee.
Since we drove from Mammoth Cave to Nashville, we'll describe the driving directions from there. Again, I'm sure there are many ways of getting to the main visitor center area for Mammoth Cave National Park, but we can only talk about what we've done.
From Nashville, find your way north onto the I-65 north. Take this freeway for about 84 miles to the Park City exit (exit 48, which is well-signposted). We then turned left onto KY255 and followed it (becoming Hwy 70 after 2.3 miles) for about 4.6 miles. Then, we turned right to leave Hwy 70 but continue on the Mammoth Cave Parkway for another 8 miles. The large car park and visitor center are at the end of the public section of road.