This post may contain affiliate links. Please read our disclosure.

Nothing moves in the sprawling underground labyrinth. The only sound comes from a slow, steady drip of water into the Billion Gallon Lake. Later, there will be a low rumble of pumps extracting the inch of water that accumulated overnight, but for now, it’s only the incessant drips that distinguish one second from the next for Bonnie and Terry.

Life wasn’t always this easy for these two smallmouth bass. There was a time, almost a decade ago, where they swam in a lake in Missouri, in a life filled with the usual fishy fears. Is today the day we’ll be eaten? What’s our next meal? What foul creature lurks around the next corner?

Top of the Billion Gallon Lake 4
Top of the Billion Gallon Lake 2

Life became much simpler when they moved into the Billion Gallon Lake that fills the lower three levels of the abandoned Bonne Terre Mine. They instantly became the top, middle, and bottom of the food chain as the only two living creatures in the lake, save a few freshwater shrimp feeding on timber scraps.

Not only do the days and nights bleed indistinguishably from each other, but so too does summer and winter. The water is always 60 degrees, with no thermoclines and no current. Ironically for Bonnie and Terry, this is the magic temperature that signals spawning time for smallmouth bass. In a way, it’s perpetual spring.

Top of the Billion Gallon Lake 3
Top of the Billion Gallon Lake

It’s hard to say if they remember moving day. It would be strange enough to view the world from a plastic bubble of water, much like the view from a diving bell for air-breathers visiting underwater. Only the walking route through Bonne Terre Mine is foreign to all living things. The block and pillar mining process left behind massive voids of support pillars of untouched bedrock. Here you can still see the lead veins that drew miners to the lead belt for centuries. Lead was so abundant that indigenous civilizations would find it at the surface and use it for tools and weapons. Starting in the 1860s, steam power, explosives, and teams of mules extracted the entire deposit over 100 years. The seams in the support pillars are all that’s left from one of the world’s richest lead deposits since their removal would cause the mine to collapse.

Do Bonnie and Terry remember walking past the tour’s mining vignettes? Do they remember seeing the New Madrid Fault Line that brought the lead to the surface in the first place? This is the same seismic zone that caused the devastating Herculean Earthquakes in 1812. Did they see the multicolor crystals seeping out of the cracks and resolidifying in frozen pools of rock?

READ
Romero Pools: Tucson's Other Hiking Trail With Water
Train track in the Bonne Terre Mine
Mineral deposit at the Bonne Terre Mine

Our fishy friends certainly remember the dock on level two. This is where they’re fed and spend most of their time, greeting each boatload of tourists as they embark on the boat tour of the Billion Gallon Lake. The tourists see only a tiny fraction of the 17-mile subterranean shoreline. Bonnie and Terry get to explore all of it.

It isn’t fair to say that every day is the same. The weekends bring a whole new group of visitors. These are the weird ones who dive into Bonnie and Terry’s home. They enter at the dockside dining room decked out in 7-mil wetsuits or even drysuits. The new ones spend their time on the first four routes getting the lay of the lake.

Bonne Terre diving sign
Boat at the Bonne Terre Mine
Docks at the underground lake

The divers pass by the old ore carts, the elevator shaft, dynamite boxes (where the yummiest shrimp live), and even the stack of old magazines. Bonnie and Terry know the guides. They’re the ones with the powerful flashlights who keep coming back almost every weekend to take a new group through.

Bonnie and Terry might recognize the regulars. They’re the ones who came back for another weekend to explore past the first four routes. They’re the ones who go to the old steam engine and timekeeper’s cabin. However, neither the guides nor the regulars have made it down to the depths of the 5th level. The treasures there, like the abandoned cafeteria, are for the fish alone.

Into the depths of Bonne Terre Mine
Mine cart light and shadows at Bonne Terre Mine
The smoke room at Bonne Terre Mine
Mine cart in narrow passage in the Bonne Terre mine

Things could have been different for our gilled duo. Doug Goergens, the one and only owner of Bonne Terre Mine and West End Diving, had other plans. When he opened West End Diving in 1960, he imagined building an entire aquarium full of life. That was until the one and only Jacques Cousteau came to visit.

Cousteau fell in love with the Bonne Terre mine. He dove all around the world and had never seen a place like this. When he heard about the plans to introduce fish on a large scale, he said – “Man has adulterated the Earth by mining it out, and mother nature has reclaimed it, creating a pure and unique ecosphere.” He knew there are thousands of places to dive with fish, but only one Bonne Terre Mine with crystal clear water and the remnants of a 100-year old mining operation abandoned and left nearly fully intact when they shut the doors in 1962. Doug heeded Jacques’s advice and halted his plan to acquire additional friends for Bonnie and Terry.

READ
Boutique Travel - Everything You Need to Know to Have Your Best Vacation Ever
Elevator structure in Bonne Terre Mine
Magazine underwater at the Bonne Terre Mine
Flooded ladder at the Bonne Terre Mine
Ed in the elevator structure at Bonne Terre Mine
Time Keepers shack at the Bonne Terre Mine
Sunken boat in the Bonne Terre Mine

If you want to visit Bonnie and Terry, in their namesake town and mine, it’s about an hour south of St Louis, Missouri. The Bonne Terre Mine is open for walking tours daily during the summer and Fri-Sun at other times. If you want to become a deep earth diver, West End Divers is a full-service dive shop that offers tours every weekend and gear for rent or purchase. You can even book a full weekend and stay at the Bonne Terre Depot Bed and Breakfast.

Come and see for yourself why National Geographic Adventure named the diving at Bonne Terre Mine one of the top 10 adventures in America, and maybe even meet Bonnie and Terry along the way.

The Depot and Caboose Bonne Terre Missouri_
Disclosure: A big thank you to Visit Missouri and the Bonne Terre Mine for hosting us! For more Bonne Terre Mine inspiration check out their InstagramFacebook, and Twitter accounts. For more Missouri inspiration check out their InstagramFacebook, and Twitter accounts.

As always, the views and opinions expressed are entirely our own, and we only recommend brands and destinations that we 100% stand behind.

Like it? Pin it for later on Pinterest!

Images of diving Bonne Terre Mine
Diving Bonne Terre Mine

We are excited to share our journey with you!

Join the Concierge Club for behind the scenes content, our latest posts, and more…

Straight to your Inbox!

`