By Alex Schechter
January 20, 2016
Mega Cavern

Louisville’s Mega Cavern may not be a natural cave system, with stalagmites and stalactites, but that doesn’t make the world’s first and only underground zip-line course any less spectacular.

Housed in a 100-acre cavern created out of a 19th-century limestone quarry, the adventure tourism operator hides out underneath ten lanes of the I-264 highway (not to mention parts of the Louisville Zoo, a Kmart and a Wendy’s), and it’s technically classified as the largest building in Kentucky, even though it’s not part of the skyline. Once inside, there are several activities to choose from—electric fat biking, tram tours, and aerial ropes—but zip-lining is by far the most popular.

Mega Cavern

Thousands of glowing Tripadvisor reviews attest to the uniqueness of the zip-line tour (2.5 hours, $69). Its longest line (there are six) stretches 900 feet over canyons and wobbly suspension bridges, and will have you reaching speeds of up to 45 miles per hour. As if that’s not dramatic enough, giant spotlights are set up so you can watch your shadow whizzing against the limestone rock walls.

“It’s pretty exhilarating. I think everyone leaves here satisfied,” says co-founder Jeremiah Heath, and points out that the last section is tandem-style, meaning you get to race the person next to you to the finish line. (“Bunch up into a ball,” advises Heath, “it decreases wind resistance.”)

As for safety concerns? “It’s a risky activity,” he admits, “But we’ve set the bar pretty high when it comes to safety standards for zip-lining.” Starting with the gear—harness, tethers, backup tethers, helmet, safety lamp—which is all provided. Plus, you’re attached to a guide the whole time, so you don’t have to do any of the actual braking yourself.

Mega Cavern

If, however, you’re not a fly-through-the-air kind of traveler, Mega Cavern’s indoor bike park is no sideshow. For starters, it’s the largest in the world (320,000 square feet, to be exact), with 45 trails to choose from, and is a great way to explore the entire cavern system from (sub-)ground level. You don’t have to bring your own bike, either—rentals are available year-round; though, Heath advises, weekends and school holidays tend to get busy, so try to avoid visiting during those times.

Best of all, the cavern is just 5 miles from the Louisville Airport (the perfect layover activity?), and a 15-minute drive from downtown. For travelers looking to see more of Louisville than just its caves, Heath recommends two museums, both within walking distance of each other: “The Muhammad Ali Center shows the life and history of Muhammad Ali in a very interactive way; they have a boxing arena, so you even get to participate in some boxing activities, which is pretty cool. The other is the Louisville Slugger Museum—if you like baseball, go there.”