JOLIET, Ill. - It didn't take much to turn the Old Joliet Prison into a haunted house.
The facility was built in the late 1800's, housing Civil War prisoners and some famous felons.
But some recent renovations unearthed some interesting discoveries.
Very few have willingly stepped inside the prison cells or climbed down into the basement of the Old Joliet Prison. Now, you'll see why.
It was one of the world's most notorious penitentiaries. Today, the Joliet prison is a place no one goes alone.
The building is now the site of the Old Joliet Haunted Prison. The facility closed in 2002 after housing inmates for 163 years.
"This is the limestone that the prisoners mined out of the quarry from the quarry lake here, so these walls are probably from the late 1800's," said tour guide Bryan Kopp.
There are no lights in the basement, and cells are carved into the foundation.
"It adds to the creepiness when you're down here that it's like 20 degrees colder," Kopp said.
Kopp is part of the team that assisted with the prison's remodel for the haunted house.
"Apparently, those were actual cells that they would put the disobedient prisoners in," Kopp told FOX 32.
Upstairs the original cellblocks remain, barely — once housing prisoners like John Wayne Gacy, James Earl Ray and "Baby Face" Nelson.
"We were able to get this guard tower open that we hadn't seen inside for over a year, and we get in there, and it was filled with all these old inmate mug shots," Kopp said.
There were even discoveries made outside the prison gates.
"Back in the woods, we found these old pieces of wood lying around and figured someone had just dumped something or something fell apart," Kopp said. "There was a prisoner grave yard back in the woods, right where we were exploring."
An old prison has been given new life with a history it can't escape.
"So many terrible things probably happened behind these walls," Kopp said. "And there's absolutely a sense of that history bearing down on you when you're here."
The Old Joliet Haunted Prison is open through November 6. But the team behind it hopes to hold events year-round, so you can be scared 360 days a year.