Gary Machens, who lives in the city of Alton in Illinois, has discovered a tunnel running beneath his property, which was likely built many decades ago, Fox affiliate KTVI reports.
As Machens explained, he was "doing some excavating and repacking of the rock" while fixing his sidewalk, which apparently started to slope, when he stumbled upon the tunnel.
"A lot of brick," he remarked. "Whatever they built this for, it took a lot of men and a lot of hours. You know, one guy didn’t do this."
He added that, according to local historians, "this tunnel was put in here around 1840."
"It’s been used as an icehouse or root cellar or a lot of other options," Machens mused. "It could have been used for the Underground Railroad. There’s no proof of that but there was a ferry here in the Alton area to the Missouri side and it’s possible it could have been used for that."
While he currently has to seal the tunnel, Machens is not against the idea of "opening the tunnel for tours," provided he's able to obtain help "with logistics and cost," the media outlet adds.