The Louisville Mega Cavern is a 100 acre limestone cavern capable of shrugging off a 260-mph tornado and boasts a constant 58 ... -degree temperature. The cavern under the Louisville Zoo has remained virtually dormant since the last load of limestone was mined nearly 20 years ago to build bridges and roads across the Midwest. Featuring six underground zip lines, including a fun filled dual racing zip, two awesome challenge bridges that will test your skill, balance, and mettle, this tour is guaranteed to get your heart racing and your adrenaline pumping. If you are looking for a one-of-a-kind adventure, MEGA ZIPS is the place to visit. read more