Louisville, Ky. (WHAS11) – In just four months, a major new attraction is due to open in Louisville. It’s something its developers have not spoken about publicly until now.

For decades, it was just a hole in the ground, but over the last eight years

The 4,000,000 square feet of underground space left behind from 40 years of limestone mining deep under what’s now the Louisville Zoo, has evolved from a huge high security commercial storage facility to what is now rated as Louisville’s number one tourist attraction on Tripadvisor.com.

Zip lines, a ropes course, Lights Under Louisville and now something revolutionary.

An indoor bike park.

The bike park will be made of 40 trails, which is enough room for beginners and professionals, plus a huge room for bike jumps.