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Louisville Mega Cavern

For year-round outdoor adventure, head indoors to Kentucky’s largest building. Louisville Mega Cavern, a former limestone quarry, offers ziplines, mountain biking and more, all underground.

“Louisville Mega Cavern was originally the Louisville Crushed Stone Company,” says Jennifer Quinlan, Event Coordinator for Louisville Mega Cavern. “The limestone mining business ran until the 1970s, and the space sat empty for several years before the current owners purchased it in the 1980s.”

Using recycled concrete, brick, and other materials, the owners built up the floor of the cavern to create usable space and build what is now an underground commercial storage facility. The recycling business in the Mega Cavern continues to operate today.

“The public was really interested in what we were doing, constantly seeing semis coming in, dump trucks coming in, and they really weren’t sure what was going on,” says Quinlan. “So the owners decided, ‘Let’s show everyone the really interesting things we have going on underground.’ In the late 90s they created our tram tour.”

“Our mega tram tour talks about the history of the cavern—what we are today and what we’re planning on being in the future,” says Alec Zaremba, Marketing Director for Louisville Mega Cavern. “If you’re interested in the Cuban missile crisis or mining or worm recycling, we definitely recommend you come down here and check it out.”

The cavern’s connection to the Cuban missile crisis is a fascinating part of its history. In the 1960, the space, which was still a mine at that time, was a designated nuclear fallout shelter. A secret list held the names of approximately 50,000 people who would be granted a spot in the massive underground shelter should a nuclear attack occur.

“Above us we have about 26 feet of solid rock and then above that, depending on where you are, about 50 to 60 feet of dirt,” says Quinlan. “In the areas that we have more traffic we also put roof bolts in the ceiling just to make sure that the ceiling stays completely secure.”

The cavern is classified as a building rather than a mine, and at 100 acres, it is Kentucky’s largest building. Today, rather than being a secret safe place for selected citizens, it’s home to truly unique recreational opportunities for everyone, including the world’s only completely underground zipline course.

“We have six ziplines down here in the cavern,” says Zaremba. “With that we go across three challenge bridges. It’s a big adrenaline rush. It’s the only place in the world where you can zipline 100 feet below the surface of the earth and also 100 feet above the cavern floors.”

The Mega Quest ropes course is a physically challenging endeavor for all ages.

“Our Mega Quest adventure course is 79 elements that will push you to the limits,” says Zaremba. “I think I’m a pretty fit person and I go up there and get a little thrill out of it every time.”

“[The mega quest] is easy enough for the younger kids to be on the lower level and enjoy those obstacles,” says Quinlan. “But once you get to the second level, you have the more challenging obstacles, so adults really seem to enjoy the challenge also.”

One of the latest additions to the Mega Cavern is the 32,000-square-foot mountain bike park.

“It’s the only underground mountain bike park in the entire world,” says Zaremba. “It’s all made out of dirt. Most places indoors don’t have the ability to have dirt like we do. Ours is more like an underground trail system that you would have outside at your local parks.”

The Mega Cavern is open year-round, and stays at a consistent temperature of around 58 degrees. Cavern staff keep the humidity levels managed through fans and pumps during the wet summer and fire trucks to spray the dirt roads underground to keep them from drying and cracking during the winter.

“The pressure of the cavern causes the air to circulate naturally,” explains Zaremba. “We do have fans that encourage that circulation but all those do is help move the air in its natural flow. By closing one of our doors down here we can cause about a 10-mph wind to go through the cavern to push air around, so you’re breathing pretty fresh air at all times.”

This segment is part of Kentucky Life episode #2008, which originally aired on January 31, 2015. Watch the full episode.