CINCINNATI — Researchers are trying to uncover historic safe houses that once helped runaway slaves as a part of the Underground Railroad.

In the basement of the historic Harriet Beecher-Stowe house in Cincinnati, there’s what some thought was a way to help runaway slaves.

“They look at a hole like that and go, ‘oh is that a tunnel?” said Christina Hartlieb, executive director at the Harriet Beecher-Stowe House.

Hartlieb said the hole in the basement area is not what you think.

"That's actually just a crawl space," she said. “We have ground-penetrating radar that shows there are no tunnels that radiated outside the house, and there's no other evidence there might be one."

The house may not have been a safe house, but it is a museum now. It's filled with artifacts about Beecher-Stowe, who was a renowned author who wrote about the cruelty of slavery. 

Hartlieb and her team of volunteers have been using some of the facts to find and map out places that really were safe houses, but she said it's been a challenge.

“A lot of this research is very hard to distinguish because people weren’t keeping records of breaking the law,” said Hartlieb.

It was illegal to help slaves escape in the early 1800s. That's why they used the code name known as the Underground Railroad. It's the route that led to safe houses or “stations” where slaves would hide to get to freedom. 

Slaves had to cross the Ohio River to get from Kentucky, once a slave state, to Ohio a free state, and it took them right into Cincinnati. 

“They had to come up the ravine and up the back side of the property here, and then through the back door," said Charles Thompson, manager at Six Acres Bed and Breakfast in Cincinnati.

Thompson helps run the bed and breakfast that was once a safe house. 

“How many people actually live and work in a space that actually hid escaped slaves on the third floor?" said Thompson.   

The house was once owned by abolitionist Zebulon Strong. He said the house itself proves he used to help hide slaves here.  

“You see all these weak little spaces,” said Thompson.

He said there's even a back staircase where runaway slaves could go inside to hide out until they had to go to the next stop.

“If he needed to get slaves to the third floor, this door could be shut (and) you would never know,” said Thompson.

That’s why this safe house is on the map of all the known safe houses in Cincinnati that Hartlieb was working on, but she said there’s still more work to do to uncover hidden history. 

“It’s a big project and one that we’re not sure where it’s going to go yet, but one that needs to be illuminated for everyone,” said Hartlieb.