I woke up in the Black Hills National Forest and was just about to drive off when a dog wandered past. In my rearview mirror, I saw a couple walking up the access road, so I rolled down the window and said good morning. We ended up talking for about 15 minutes. Cynthia and Todd ride mules and give mule tours, and they’re avid campers with a Class C rig. They’ll spend a month at a time in one spot—pretty common for many people now. They’re also planning a trip to Alaska next summer. I told them I’d see them up there. I forgot to mention The Milepost, the guidebook every Alaska traveler should have.

Jewel Cave – Visitor Center

From there I headed to Jewel Cave National Monument, where a big crowd had gathered for a reopening event with a walk and race. I wasn’t part of either, but it made the atmosphere lively. At the Visitor Center, two rangers greeted me right at the door, both eager to help. At the information desk, another ranger gave me a rundown of the tours, reminding me they fill quickly since only 30 people are allowed per group. He even answered two phone calls during our chat, giving callers the same information. The next tour was two hours away, so I headed outside to buy a ticket. Up the steps, another ranger pointed me to the window, where a young man sold me the ticket with real professionalism—such a contrast to the lackluster service I’d had at Mount Rushmore the day before.

**The Bigger Picture**

Back inside, I walked through the exhibits and then stopped at the gift shop. I like to support the parks, so I picked up a book called *The Practical Geologist*. It’s written at about a middle school level, which is perfect for me. After reading so many roadside geology plaques on this trip, I’ve wanted to dig a little deeper into how these landscapes actually formed.
By late morning the weather was gorgeous, so I found a bench in the sun and flipped through my new book. I read the first 20 pages before heading back to the van to make a salad and pull a shot of espresso while I waited for the tour.

Jewel Cave Tour

When the time came, I realized I’d left my ticket in the van and had to jog back for it. I made it with five minutes to spare. Our tour guide was a geologist and caver who clearly loved her job. She gave us safety rules and joked that we didn’t want to “play dominos” down the stairs, so we should always use the railings. She encouraged us to pass messages like “watch your head” through the group whenever we reached low ceilings. Most importantly, she emphasized not touching anything. At one point, she showed us touched versus untouched stone side by side—the difference was striking. Oils from human skin break down the rock surface quickly, and she told anyone with the urge to touch something to do it now, before we went deeper.

History and Exploration

Jewel Cave was first discovered in 1900 by brothers Frank and Albert Michaud, who noticed a strong wind blowing from a small hole in the ground. When they enlarged the opening and went inside with lanterns, they found glittering crystals on the cave walls. Thinking quartz might mean gold, they were excited—but it turned out to be calcite crystals, beautiful but worthless. They tried turning it into a tourist attraction, but it never really took off until decades later. In 1908, President Theodore Roosevelt proclaimed Jewel Cave a National Monument, protecting it for the future.

The true scale of the cave remained hidden until 1959, when Herb and Jan Conn, a husband-and-wife team from nearby Custer, began exploring beyond the short tourist route. Originally rock climbers, they crawled and climbed their way through narrow passages with carbide lamps and ropes. Over the next two decades, they mapped more than 60 miles of new passageways, proving Jewel Cave was one of the world’s longest cave systems. Their meticulous work laid the foundation for modern exploration, and today more than 200 miles have been mapped—though airflow studies suggest hundreds more remain undiscovered.

Mapping continues today with teams of volunteers and scientists who use compasses, lasers, and precise survey methods to document each new passage. It’s painstaking, inch-by-inch work, but it steadily adds to our knowledge of this underground labyrinth.

A Living Laboratory

Jewel Cave formed over millions of years as acidic groundwater dissolved the limestone, carving out vast chambers and twisting passages. Later, mineral-rich water deposited the formations we see today—calcite spar crystals, stalactites, stalagmites, and flowstone. Walking the tour route, you get to see those glittering “jewel” crystals up close, but the cave is also an active laboratory. Scientists study it to learn about geology, hydrology, and underground ecosystems. Knowing that this vast hidden world lies just beneath the Black Hills adds another layer to the story of this region.

Custer State Park - Visitor Center

It was 4 p.m. when I headed to the Visitor Center in Custer State Park. I saw a couple on bikes and asked about trails. The ranger at the desk seemed excited to get something other than the usual questions. He asked what type of bike I had, then disappeared into the back and returned with two maps—one for the Mickelson Trail and another showing the mountain bike trails in the park.

The visitor center has a short film called Spirit of Tatanka, narrated by Kevin Costner. His voice gives it a familiar, easy feel as it moves through the park’s landscapes, wildlife, and history. It runs about 20 minutes and does a good job of setting the stage before heading out to explore. For me, it was a nice way to settle in and get a feel for the park before starting the evening. I had already seen the buffalo yesterday.

Bike Ride

Looking at the map, I realized the 109-mile-long Mickelson Trail was about a 20-minute drive toward Custer, SD. Instead of heading there, I decided to just explore. I followed a paved path across the street and up into the mountains through many small campgrounds, but it ended after about two miles. From there I hopped onto the road and the ride another six miles uphill. The speed limit in the park is 35 mph, and most drivers were going well under that.

Deer were everywhere, grazing along the road, darting off as soon as I came near. On the other side, two pronghorn stood calmly in the grass and didn’t budge. At one pull-off I stopped to check the bike, not realizing a buffalo was lying in the grass less than 50 feet away. I wouldn’t have noticed it at all if it hadn’t let out a deep breath. We just looked at each other for a moment before I eased back onto the road.

A little farther on, I turned off onto a dirt road and came across a plaque about Charles “Badger” Clark, South Dakota’s first poet laureate. He lived in a small cabin called the Badger Hole here in Custer State Park, and his poems captured the freedom of cowboy life, the solitude of the prairie, and the spirit of the Black Hills. His most famous work, A Cowboy’s Prayer, is still read today at gatherings across the West. Reading the plaque, I imagined him writing about the same hills and pines I was riding through.

I reached the top just in time to see the golden rays of sun filtering through the Ponderosa pines. The ride down took a third of the time it took going up. Tempting as it was to let the bike fly downhill at 40 mph, I knew one mistake could end the whole trip.

Back at the van, I packed up, made burritos for dinner, and then tried to figure out why the water pump was making strange noises. It turned out I was nearly out of water—down to just two gallons—so the pump was working harder to pull from the tank. My $25 park pass allowed me to refill water and use the restrooms and showers at the campgrounds, so I pulled into one of the smaller campgrounds. I took a shower and filled the tank, though the water pressure was weak, probably because this was the highest campground in the park.

An hour later I was on my way to another spot in the Black Hills National Forest. There were so many campers in this area that I had to drive 1-1/2 miles in before finding a place to settle for the night.

Jewel Cave