Bonne Terre Mine
Beneath the historic, sleepy town of Bonne Terre, Missouri, lies a billion-gallon, 17-mile long lake inside a mine that dates to the mid-1800s. It's eerie, dark and an altogether unique experience for adventurous divers. Both the depot and Bonne Terre Mine are listed in the National Register of Historic Places.
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Mule Trail
Fortunately for the owners of the flooded mine, the miners used mules to help haul ore and equipment in and out. Divers and those on dry walking tours must descend 1/4 mile and down the 65 steps into the heart of the mine and to the docks. The trail and caverns were all carved using hand tools.
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Consistent Temperatures
Run by [West End Diving](http://www.westenddiving.com/), the water and air temperatures don't vary much, regardless of what's happening up top. The air temp is a constant 62 degrees F and the water is generally a chilly 58 degrees F. There’s no thermocline to worry about.
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Into the Abyss
Some of the underwater scenes in the movie _The Abyss_ were filmed in these waters, so the mine has had its own bit of stardom. The chilly water in the mine fills 88 miles of passages while the surface has 17 miles of navigable shoreline, so there’s plenty of room to film your own movie.
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You can see forever
Visibility is easily around 100 feet (30 m) with very little silt on the bottom to muck it up. While the deepest parts are over recreational limits, most dives are done between 40 and 60 feet (12 to 18 m).
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The past meets the present
Once they stopped the work in the mine, the water pumps were turned off and the massive caverns were allowed to fill. Remnants of the mine's past can still be seen littered around. Divers can see ladders, scaffolding, carts and even tools while diving.
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Look up
There are limitless opportunities for silhouette shots. So while the rule against hand-held lights, camera flashes, and strobes may at first seem daunting to a photographer, it's still easy to find your shots using what light is available.
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Light from the top and bottom
The mine is dark and deep in many places, despite the 500,000 watts of surface lighting in the mine. Two guides, one in front and one trailing, carry multiple lights to make sure you don't miss a thing. Sometimes they even use them to give you some interesting perspectives.
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Night diving
The diving done here is quite similar to night or even dusk diving elsewhere, minus carrying your own light. But don't stress about not having one; in addition to the guides, a kayak also follows on the surface for divers who run low on air and need to end their dives early.
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Swim through it
If you like tunnels and swim-throughs, interesting lighting arrangements, crystal-clear water, zero current and just relaxing while swimming under a town, then you should head to Bonne Terre.
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Easy Entry and Exit
There's a large deck at the water's edge with a hang bar right below at 15 feet (5 m) for safety stops. A submerged platform floats up and down depending on how much weight is on it to allow for easy exits.
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Tec Diving
Techies, don't feel left out. While most of the 28 trails are well within recreational limits, the owners are in the process of developing three more specifically for technical diving.
