MAQUOKETA, Iowa - Before entering the caves you have to listen to a short program.
"The clothing you're wearing here don`t wear to any other cave systems, if you want to wear the same clothing you wash in high heat, dry in high heat, wash with bleach," said Carly Christenson, naturalist.
Wipe off your feet on the mat and then you're ready to head down into the caves to explore.
Nick's been going to the caves since he was little and this time he brought along a first timer.
On the adventure there's something that they didn't see, bats, which is a concern because of a fungi that infects bats called White Nose Syndrome.
"We`ve been on the suspicion list for a while so it was only a matter of time before we found a bat with the fungi on it," said Christenson.
Concern about the spread closed the caves back in 2010, they re-opened but with new precautions to help prevent it.
"It`s a 95 to a 99% kill rate so if they do have it our bat population is really gonna go down," said Christenson.
It's spread by humans going from one park to another and it hasn't stopped people from exploring, the park saw 225,000 visitors last year, so they have to be extra careful and make people aware of this deadly bat disease.
For Nick and Brody they say even though they didn't see any bats they'll continue looking and coming back to the caves.
"I just love nature, I love being outside, love exploring new things and every time I come here something new happens, something exciting," said Nick Dilley.