National Park Number: 27 of 59
We’ve been to a few caves so far in our tour of the national parks—Wind Cave in South Dakota and Lehman Cave in Nevada—which both had lots of lovely formations and decorations. Mammoth Cave is a different beast; the longest cave system in the world (by a long shot) at 412 measured miles—and scientists think they’ve discovered less than half of the cave. The reason it’s so big is because above the limestone that the cave was carved out of, there is a 60-70 foot layer of sandstone and shale that acts as a caprock, protecting the layers beneath from eroding or collapsing. The caprock does such a good job of sheltering the cave that there are only a few places where water seeps in and forms speleothems like stalactites and stalagmites. So Mammoth is not a very decorative cave.
What it is is massive, with grand passageways, expansive rooms, and gorgeously scalloped tunnels. We wanted to spend as much time as possible underground during our visit (both because we love exploring caves and listening to rangers talk about the parks, and because there were some nasty storms aboveground while we were there), so we signed up for two of the classic tours: the Historic Tour, and Domes and Dripstones.
We started off with the Historic Tour, and it was a perfect introduction to the history and geology of the cave. We entered through the Natural Entrance near the visitor center and wound down through a wide hallway to the Rotunda, an enormous space 140 feet underground and directly under the Mammoth Cave hotel.
In the Rotunda, we learned about the mining history of the cave. Prehistoric Native Americans explored the cave and went at least 17 miles in; we don’t know much about what they did there, but we do know they mined gypsum by using mussel shells from the nearby Green River to scrape it off the walls. They used the cave for 3000 years, then left for unknown reasons; it was empty for 2000 years before it was "rediscovered” by John Houchin in the 1790s when he was hunting a bear and the bear disappeared into the cave.
In modern times, the cave was first used for salt petre mining, which was used to make gunpowder. During the War of 1812, Britain cut America off from its ports so no one could import gunpowder. Mammoth Cave became a vital resource for the war; it’s estimated that 1 of every 7 bullets fired during the war was made from materials mined at Mammoth Cave. After a while, the mining petered out—and in fact, that’s where the phrase “petered out” came from (I was utterly delighted to learn this fact.)
The mining was performed by slaves, as much backbreaking labor was in America. After the war and the depletion of salt petre, the cave owners were looking for a new way to profit off their land and decided to open the cave for tourism. In 1816, the first tourists were led underground; their guides were slaves. The most famous of these was Stephen Bishop who arrived when he was 17 and turned out to be an extremely talented guide who loved being in the cave. He singlehandedly discovered 20 miles and made a map of the passages from memory that is still known for its accuracy.
Most visitors to Mammoth Cave were extremely wealthy: it was a remote area and expensive to get to. So when people came, they stayed a while and spent as much time in the cave as possible. These were people who normally would never have talked to slaves, but underground, they were entirely at the slaves’ mercy for their safety and entertainment. They talked and ate together, forming relationships that couldn’t take place outside in the daylight.
The guides were allowed to make money from tips, and one of the ways they earned tips was by smoke writing. They used tallow candles to write the names of visitors on the cave walls with puffs of smoke.
The ranger for our tour was fantastic, but because our group was so massive, she only spoke when we were all gathered in a few of the big rooms. The rest of the time we just walked and looked around, completely wowed by the scale and naturally carved passages. The tour took us through the earliest-explored portions of the cave, including tight sections called Fat Man’s Misery and Tall Man’s Agony. More than other caves we’ve been to, Mammoth’s tunnels felt very natural: the park didn’t use a single stick of dynamite in forming the tour routes and we were asked to squeeze and duck and shimmy around in places. It’s wasn’t technical caving or anything, but it was a lot of fun.
The national park was approved in 1926 during a push to establish more parks east of the Mississippi; it was established in 1941 (the NPS spent the intervening years buying people out of their property.) There are 70 cemeteries within the park’s boundaries, which is one of the reasons Mammoth Cave doesn’t charge admission—they promised the people would always have free access to visit the deceased.
The cave has roughly five levels, and on the lowest are several rivers. Til the 1970s, the park did a boat tour of the River Styx, which sounds like the coolest ranger tour in the entire world, but they stopped it because there are several endangered species that live in the river, including a shrimp that lives nowhere else on earth.
After we left the cave, we hiked down the hill to see the Green River (which is accurately named) and the opening where the River Styx flows out of the cave. Soon after, the wind got all ragey and the sky dumped buckets on us and we hid in the bus for the rest of the day, playing with Margi’s new birthday presents.
The next day, we returned for the Domes and Dripstones tour, which explores an entirely different area of the cave, including the only 1/8th of a mile of cave decorations. This tour was a blast—lots of squeezing and sidling, and a small but abundantly beautiful area of stalactites, stalagmites, columns, soda straws, cave bacon, cave popcorn, drapery, and a massive formation known as “Frozen Niagara”. We learned more about the geology of the cave, and when our ranger was talking about how carbonic acid carves the tunnels, she asked if we would drink a glass of carbonic acid. We said no; then she asked if we’d drink a can of Coke and all the kids in the group yelled “NO!”, which sort of ruined her object lesson, but it gives me some hope for the youth of America (Coke is about 1000 times stronger than the carbonic acid that formed the cave, just BTW.)
After we resurfaced, we walked out to Sand Cave, where cave explorer Floyd Collins was trapped and, after much hullabaloo, media coverage, and ineffective rescue attempts, died of exposure after 18 days. Which was a pretty sad way to end our visit.
I am easily claustrophobic and hate being squeezed; I’m also broad-shouldered and very tall, so clearly I’m a terrible candidate for caving. But I do absolutely love exploring caves the way we did: on easy, guided tours with no chance I’ll get stuck anywhere. Of the caves we’ve been in, Mammoth is so far our favorite. The scale was so enormous that it was hard not to be bowled over by the geology and history of it; as David said, “This is what you want a cave to be."