Venturing into the underground labyrinth of Mammoth Cave to see the Frozen Niagara waterfall

Welcome to Mammoth Cave National Park, the home of the longest known cave system in the world

After our relaxing hikes at Bernheim Forest on Saturday afternoon, we drove further south to the town of Bowling Green, where we stayed overnight.

If you are a lover of fast and shiny cars, you may be interested to hear that Bowling Green is best known for its National Corvette Museum, which documents the world history of the Chevrolet Corvette.

Early on Sunday morning, we backtracked north to Mammoth Cave National Parkarguably the most famous attraction in the state of Kentucky. Located halfway between Louisville and Nashville, Mammoth Cave is the world’s longest known cave system, with over 390 miles (630 km) of interlinked caverns and passageways having been explored and surveyed so far and new sections of the cave still being discovered. It is estimated that the underground system may cover as many as 1000 miles (1600 km). Not all the caves in the park are linked to the main Mammoth Cave system, however; there are more than 200 additional disconnected or separate caves. (Mammoth cave website)

Arriving at the Visitor Centre

The caves are located in a so-called karst landscape: this type of landscape is characterised by the prevalence of subterranean limestone caverns that have been carved out by groundwater, often leading to the gradual – or sudden – formation of sinkholes and to the sudden disappearance of surface streams as these sink below-ground. Over the centuries, this has given rise to an undulating landscape with numerous depressions.

In the case of Mammoth Cave, an almost impenetrable sandstone cap lies ontop of massively deep strata of limestone. This sandstone cap has been weathered away at a slower rate than the underlying limestone layers. (From: Karst Geology, PDF document available on Mammoth cave website.)

It is very cold, with the wind further lowering the temperature – nice to have such a cosy warm jacket!

Underground rivers have carved out numerous passages and caverns, while water dripping down vertical cracks from above has created extraordinary speleothems, which is the collective name for cave formations or mineral deposits found in a cave. These include the well-known dripstones (stalactites, stalagmites, and columns) and the sheet-like flowstones (draperies or curtains, dam-like rimstones, and ‘frozen’ waterfalls). (For a series of remarkable photographs of cave formations, have a look at the Virtual Cave. website.)

Archaeological evidence shows that human beings first visited these caves more than 6,000 years ago; from human remains found in the caves, it is clear that the caves were used as ceremonial burial places, as well as in the extraction of precious minerals.

A small waterfall gushes through the ceiling of this rock chamber

Mammoth Cave and the nearby Dixon Cave were only discovered by white settlers in the late 18th century. During the War of 1812 (which was fought between the United States of America and the British Empire), the then owners of these two caves exploited the deposits of nitrates of calcium and potash they found underground, to extract saltpetre (potassium nitrate or KNO3). This was an essential component of gunpowder, which was used by American soldiers.

By the end of this three-year-long War, though, the value of the two caves fell and they were sold. From 1816, for about a century, a succession of private individuals owned the caves, exploring them and offering cave tours to curious visitors. I read somewhere that the first hotel was established here as far back as 1814, near where the current Mammoth Cave Hotel now stands.

One of the best-known and respected cave guides – and cave explorers – of that time was an African-American slave by the name of Stephen Bishop (he is buried in the Old Guide’s Cemetery on the Heritage Trail). Visitors from near and far, whom he – and many other African-American slaves – guided through the underground labyrinths, were impressed by his knowledge of the caves. Many of these guides’ descendants – farmers, teachers, timbermen and musicians – still live in the area. (More information about the fascinating history of Mammoth cave can be found via this link, and there is even a marvellous online book to be found here, with audio narrations.)

Our knowledgeable ranger leads our group down into the depths of the earth, where we admire the beautifully illuminated dripstone formations

In 1926, essentially in order to protect the underground system, US Congress authorised the formation of a national park, and after years of legal wranglings, Mammoth Cave National Park was finally created in 1941. The park was declared a UNESCO World Heritage site in 1981 and an International Biosphere Reserve in 1990. (From: A short legal history of Mammoth Cave, PDF document available on Mammoth cave website).

Do not limit yourself to exploring the caves, when you visit this extraordinary place – above ground, too, there are many miles of trails and rivers to explore – on foot, by canoe, as well as on horseback – and plenty of camping and picnic sites invite visitors to linger for a while in this vast and beautiful wilderness. The animal and plant life is extraordinarily diverse here.

“Mammoth Cave National Park is home to over 70 threatened, endangered or state listed species. These species include birds, crustaceans, fish, gastropods, insects, mammals, mussels, plants and reptiles.” (From Mammoth cave website).

Magnificent stalactites, deep underground

The local bat population was facing a serious threat, however, in the form of a fungal disease known as White Nose Syndrome, which is spreading rapidly throughout the north-eastern United States, in some cases with a mortality rate of 90-100%. The fungus (Geomyces destructans) is new to the US, having only been discovered there in 2006.

As the name suggests, it covers bats’ muzzles, ears and wings, causing extreme irritation among hibernating bats. This wakes them up from the energy-preserving sleep that would get them through the cold winter. If they use up their energy reserves too soon, and if it is still too cold outside to forage, they will starve or freeze to death.

As bats are a vital component of the ecosystem, by eating insect pests, dispersing fruit seeds and pollinating flowers, the deaths of so many bats will have a devastating effect on the delicate ecological balance. Moreover, the most affected bat species have long lifespans and only produce one offspring a year, and thus their populations will take a very long time to recover (from: Mammoth cave website and Wikipedia).

A well-laid boardwalk with railing makes the Heritage Trail accessible by wheelchair

Signs everywhere warned visitors not to bring any clothing, footwear or handheld items into the caves that had previously been in any other caves, particularly in the North-eastern US. We were also required to walk across a Lysol-impregnated bio security mat after our cave tour, in order to disinfect our boots. And visitors who had previously been to caves in this region, were asked to have their shoes disinfected before they went on a Mammoth Cave tour as well. Hopefully these measures will reduce the spread of the disease.

Like the animal life, the plant life too is extraordinarily diverse – with the park supporting more than 1300 species in its roughly 52,000 acres. This diversity can be attributed to the unique location of the park:

“Mammoth Cave is located in the transitional zone between the open grasslands and drier oak-hickory forests to the west, and the more moist mixed mesophytic forests to the east. It is likewise located transitional between the sub-tropical climates to the south and the colder climates to the north. Many of the plant species found in the park are at the northern, southern, eastern, or western limits of their natural range.” (From Mammoth cave website).

A cluster of cheerful daffodils

We were intending to join one of their cave tours. Interestingly, the cave can be visited throughout the year, as the temperature inside the cave remains at a fairly constant 54 degrees Fahrenheit, hardly fluctuating with the seasons. Electric lighting is used on most of the routes, though old-fashioned paraffin lanterns are used too, giving you better insight into the challenges the early cave explorers must have faced (e.g. on the nostalgic Star Chamber Tour and the Violet City Lantern Tour that will take you to numerous historic landmarks). The lantern-lit tours aren’t recommended for people with respiratory illnesses.

After considering all the options, I chose the shorter, less potentially panic-inducing Frozen Niagara Tour (1 1/4 hour). Described as ‘easy’ and ideal for people who want to see some beautiful stalactite and stalagmite formations and flowstones, etc., without spending too much time underground, it sounded just right for me.

A colourful carpet of leaves – and far below, the Historic Entrance, the largest natural entrance to the world below. It has been in use since 1816, for almost 200 years.

I don’t like enclosed spaces much; moreover, in my experience, cave guides seem to get a perverse pleasure out of announcing exactly how many metres we are below the ground, and how many tons of rock are currently poised above us… which always raises that disturbing niggling question in the back of my mind: What happens if there is a tremor or an earthquake? Are we going to be buried alive? Honestly, this isn’t how I would like to spend my last moments on earth.

My fearless significant other is enviably free of such anxious musings. I think he would’ve been quite willing to do one of their longer and more strenuous adventure tours. Given the timetable limitations of the tours available on that day, however, he chose the New Entrance Tour (2 hours), which was described as “A wonderful complement to the Historic Tour, this trip includes a dramatic series of domes and pits, typical large trunk passageways, a short journey through dripstone formations and stairs, stairs, stairs!” It also included the Frozen Niagara Tour route, so we would end up seeing the same part of the cave, albeit at different times.

This is known as the old guide’s cemetery

For those among you who long for the thrill of a proper getting-thoroughly-dirty spelunking adventure, there is the – no doubt appropriately named – Wild Cave Tour, with a “very strenuous” difficulty rating. Before you sign up, bear in mind that this tour is limited to individuals whose chest or hip measurements do not exceed 42 inches: “if you are larger, you cannot physically pass through the crawlspaces”, the brochure cautioned.

This is the stuff of my worst nightmares – stuck in some pitch-dark place, unable to move forward or backward, disoriented and breathless, panicking… – extraordinarily, others clearly feel quite differently about it: While we were waiting for our tour to start, a group of about 10-15 young-ish people, all wearing sturdy boots and protective overalls, as well as hard hats, torches and knee-guards, set off on their spelunking adventure. Brave! (Here is a YouTube clip of the 6-mile, 6-hour tour that was filmed by one of the participants – it should give you an idea of what to expect if you are courageous – or crazy?! – enough to sign up for one of these.)

I continue to follow the paved walkway as it loops around the back of the cemetery

Fortunately, our group included half-a-dozen little ones, whose uninhibited excitement and delight at the wonders of the myriad cave formations completely distracted me from my own anxieties. Seeing the so-called Frozen Niagara waterfall – a flowstone cascade 75 feet high and 50 feet wide – at the bottom of a very tall staircase tower, was awe-inspiring and very humbling. These formations have taken eons to be formed, one droplet at a time, and it is impossible not to feel very, very small in relation to such a miracle of nature.

On our way back to the surface, our guide pointed out a few of the different kinds of creatures – more than 130 species – that live in the caves. Among others, she showed us cave crickets and little spiders that were weaving nests in dark crevices and corners. She added, with a mischievous chuckle, that she doesn’t like to tell people about the creepy-crawlies on the way in, but only once they are on the way out. Thanks! I appreciate that!

I have a brief picnic on one of the benches at this lookout point

Trogloxenes (cave visitors) are animals that regularly visit or hibernate inside caves, but collect food on the surface (e.g. bats, cave crickets, pack rats). Troglophiles (cave lovers) can survive both underground, as well as above ground, where they would choose cool dark places that resemble the cave environment (e.g. crayfish, salamanders, spiders). Troglobites (cave dwellers) are highly adapted to cave life, and in fact cannot survive outside the cave. Some may have no eyes, having developed their other sense organs instead; others may have no pigmentation, because they do not need to camouflage themselves in the darkness of the caves, or because they do not need protection from the sun (e.g. eyeless fish, Kentucky Cave shrimp). (From: Biology and Cave Life, PDF document available on Mammoth cave website)

By the end of my walk in the cold wind, my fingers (which held the camera without gloves) are sooo cold that the tips are burning – and the icy air is literally taking my breath away… I seek shelter in a curio shop

Although it had been interesting to learn about life underground, it was very nice to step out through the protective airlock into the chilly air outside once more. Deeep breath!

I was a tad disappointed, though, to learn that the word ‘mammoth’ in the name of the cave does not refer to a woolly mammoth that might have lived here in prehistoric times. No, ‘mammoth’ is an adjective referring to the vast size of the underground network of caves. So now you know.

Back at the Visitor Centre, I had about an hour to wait before Richard was due back from his tour, so I went for a leisurely stroll across the bridge to the start of the 0.3 mile (0.5 km) Heritage Trail, a well-made boardwalk that is accessible to wheelchairs near the Mammoth Cave Hotel. A nearby sign says:

“The feet of woodland Indians, longhunters, slaves and old cave guides have passed this way, all sharing a common heritage – the hilly country, the Green and Nolin Rivers, and the great underground labyrinth that make Mammoth Cave National Park unique.

Add your steps to theirs.”

And when Richard’s tour is finished, we warm up with two rich and creamy hot chocolates – the best!

So I did. I followed the Heritage Trail past the various information signs, and had a relaxing picnic on one of the benches at the lookout point. As I gazed out at the forest and the mountains beyond, I couldn’t help marvelling at the fact that we were actually inAmerica, and that we had almost-but-not-quite two exciting weeks left on our little roadtrip, before we had to get on the plane back home. Although it was beautiful and so peaceful here, I did not stay long. The wind was picking up, more and more clouds were scudding across the sky, and I could feel the temperature dropping.

Eager to get out of the icy wind, which was literally whipping my breath away, I made my way back to the end/start of the circular Heritage Trail, and sought shelter inside one of the curio and book shops. My hands, which had been clutching the camera, were so cold and stiff by then, that my fingers were throbbing with pain, and I could hardly pick up any of books on the shelves. When Richard finally returned from his tour, we both had a rich and creamy hot chocolate inside the cosy restaurant to warm ourselves up from the inside. Ohhh, heaven.

Before leaving the park, we briefly drove down to the nearby river to check out the ferry. The Green River, a tributary of the Ohio River, winds its way across the terrain, draining the cave system and leisurely curving around the forest covered hills.

Magic… I hold my breath… and then they scamper off into the woods, their white tails flashing

This river was canalised in 1842, with a series of locks and dams making it navigable by boat for much of the way. In the past, a whole number of ferries gave access to the other side of the river, but only two of these ferries – the Green River and Houchin ferries – are still in use today (Wikipedia).

As we drove down towards the river, the forest dense on either side of the paved road, we spotted a herd of white-tailed deer up ahead on the grass verge.

Pulling off on the side of the road, I quickly put on my telephoto lens, and managed to snap a few photos, before the deer scampered off into the undergrowth, their bushy white tails flicking upwards. A magical moment.

The car is delivered safely to the far side of the Green River.

Down by the river, we stopped on the empty parking lot next to the Green River Ferry Crossing and I clambered out to take some pictures. Strong and thick cables, securely anchored in the ground, criss-crossed the river at this point. The river was fairly wide and sluggish here, and a small motor-driven ferry – just large enough for one (or perhaps two) cars – was anchored on the far side, held by two cables on each side.

Just then, a landrover approached from behind us; it stopped obediently next to the Stop sign, and waited for the ferry to make its way to our side, before driving onto the platform and crossing safely to the other side. Our stop here had been amazingly well-timed!

In the meantime, Richard had entered our next destination into the Garmin navigator: Nashville, Tennessee! It was time to head south, to the Home of Country Music!

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32 thoughts on “Venturing into the underground labyrinth of Mammoth Cave to see the Frozen Niagara waterfall

  1. Nice post, Reggie. I thought I’d seen enough limestone caves (with coloured lights and silly names for the formations) to last me the rest of my life, but I might make an exception for the Mammoth Cave – anything with wildlife in it will keep me interested.

    • As long as you don’t expect to meet a woolly mammoth face-to-face, Richard… 😉

      We didn’t see much wildlife, other than cave crickets and spiders, actually, and I didn’t get any good pictures of them – if you use an on-camera flash, it over-exposes the image, and the camera struggles to establish a focus, when it is so dark… even when the guide was shining a torch on the creatures she showed us, they didn’t keep the light steady enough to give the camera a chance to focus, but flicked it back and forth on the cave walls, which didn’t help.

      As far as larger animals are concerned, we probably made far too much noise, and I’d guess that most of the animals would probably avoid the tourist routes.

  2. I’m so enjoying your view of so many places I’ve been and love. I’ve been to Mammoth Cave several times, starting when I was about 10. There is always something new to see. You made good choices of what to see in the short time you had. Something interesting: when I was a child there was a mummified Native American who died in the cave on display in a glass case which we passed on what was then called the Historic Tour. He has since been moved to a more dignified final resting place.

    I never had a fear of caves but I remember being terrified of climbing the fire tower-like staircase at the end of the tour. My mother said she did not think she was going to get me out of there!

    • Thank you, Malou. Yes, I noticed that from the type of blog posts you write: you often write about the beautiful natural places in the Netherlands that you have visited with your adorable family.

  3. Reggie, I think I visited this cave as a child. Not 100% sure (would have to ask Mom or Dad) but it seems and looks familiar. Remember marveling at stalactites and stalagmites and Mom quizzing us about the differences afterward. Thank you for the lovely tour as an adult! By the way, I did visit a cave in Montana a decade ago and sat underground. The lights were extinguished and we deeply connected with our spirituality while deep in Mother Earth. A fascinating experience!

    • I am delighted to hear that you may have visited Mammoth Cave as a child – glad you enjoyed the tour again. The spiritual cave experience sounds amazing… I can well imagine that it must have a profound impact on one’s psyche.

      • You’ve got to try it, Reggie! Especially the soft singing in the damp dark cave of the earth…and the echoing silence. Hope you get to experience it some day.

      • Wow… you make it sound quite appealing and beautiful, Kathy. If the opportunity ever presents itself, I will try to keep an open mind about it. And I will share my experience with you afterwards. 🙂

  4. Great entry! Mammoth Cave is definitely worth visiting – it’s been a few years since I last visited, but I remember it being pretty incredible, and of course all of Kentucky is a beautiful state to see.

    I recently read this book which I found to be really fascinating – “Beyond Mammoth Cave: A Tale of Obsession in the World’s Longest Cave” by James D. Borden and Roger W. Brucker. They helped discover additional cave networks that resulted in Mammoth Cave being three times longer than any other cave system in the world. Well worth the read even if you aren’t a die-hard cave junkie.

    • Thank you! I agree with you – based on the parts of Kentucky we saw, I would love to explore more of it, because it sure has tons of natural and beautiful wilderness areas. Thank you for the book recommendation; those intrepid cave explorers, particularly of the early years, sound absolutely fearless. I honestly cannot imagine what could compel someone to squeeze through a small crack in the rocks, with the vague hope that he just might emerge safely in a beautiful cave, deep inside the earth, with never-seen-before rock formations etc. How they do not lose their sense of orientation in that darkness, is another miracle I cannot get my head around! I’d like to read that book to gain a better understanding of what drove them.

      P.S. By the way, your website is STUNNING! 😀

  5. Hi Reggie,
    Perhaps because I’ve never been to Kentucky but I had no idea that there was such a vast network of caves there. Thanks to you I now know.
    Very sad to hear about the bat disease – I recently read something on bats that made me rethink their story. I don’t know why they became connected with all things evil because they are very smart creatures. Imagine being able to fly in the dark without anything other than hearing to guide you…

    When we were in South Africa we visited “Sterkfontein Caves”. And while we were way the heck underground (forget how many meters it is) there was a very fierce summer thunder storm which KNOCKED OUT THE LIGHTS under ground every time the lightning hit the earth i.e SIX times leaving us in the pitch dark. As a coincidence we’d given our two friends (who were our tour guides that day), a gift of a wind up flash light (torches) from my Museum. They sure were a godsend in the dark caves. We ended up with a large group walking very close to us…

    • When I was still in school, our biology teacher was fascinated by bats; at the time, I didn’t fully understand how intelligent they are or what a vital role they play in the ecosystem, and just bought in to all the hysteria about them flying into your hair and getting stuck in it when you’re in a cave – which doesn’t exactly make one feel comfortable about venturing into caves in the first place.

      A day ago, we saw a video, in which a blind man was filmed, while he was cycling through a park. He was using echo-location to navigate and to double-check that the path ahead was clear of obstacles! Can you imagine? He made these funny little sounds, that apparently created an echo back to him.

      We haven’t visited the Sterkfontein Caves, though no doubt they are on Richard’s “oh, I definitely want to see those!” list. He likes caves. 🙂 I cannot imagine how frightening it must have been to be stuck down there without any light! Well done on bringing along wind-up torches! I’ve seen some wind-up ones here too, they’re a very clever idea; there are also ones that you shake for a while in order to charge them. An excellent back-up system – usually the batteries are half-dead when you really need the torch!

  6. The Mammoth Cave National Park looks like quite a special place. I have been in many caves, but this one looks like a spectacular place. You writing and pictures makes it very interesting to follow you along. Thanks for an inspiring post.

    • That is such a nice thing to say, Paprika, thank you. 🙂

      I have been rather quiet on the blogging front, because I’ve been doing a couple of different courses, but hopefully I shall be back soon!

  7. I visited the caves when I was 9 years old, on vacation with a neighbor’s family. It was an experience I’d never forget; compelling, mysterious, and oh so scary for a young child. I’ve learned a lot about the caves reading your post…good memories!

    • Thank you so much for your comment, Monica – I am really delighted this post brought back some happy memories of your childhood; there were several small children on our tour of the Frozen Niagara – I wonder how many of them will remember this visit when they are older, and how they will feel, looking back on it. I hope it will also re-awaken some magical memories. 🙂

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