A building demolition in the Dundee neighborhood unearthed a mystery.

What appears to be a sealed door has work crews and folks at the Durham Museum scratching their heads.

"I thought the same thing I think a lot of people thought," Harlan Jentz said. He's part of the crew filling in this pit with dirt. "It was just a way people smuggled whiskey during prohibition."

Jentz' theory on prohibition being a possibility is shared by Tim Lambert, also a part of that work crew.

"Maybe during prohibition, they stored liquor under there, I don't know," Lambert wondered.

The pair says one thing is very obvious, the concrete is old. They believe it might actually have been poured from the other side that isn't exposed.

Sealing away a mystery, simply marked with the number 56.

We took our quest for answers to the folks at the Durham Museum, specifically to the photo archive.

That's where we met Bill Gonzalez.

"Interesting, it really is," Gonzalez said. "I would really like to know what's behind those sealed doors."

He took one look at the photo 6 News showed him and he was hooked.

"To spend that kind of effort and money to seal up those entrances, it makes you have to wonder," Gonzalez said.

We looked through photos from the photo archives to see if that could shed some light on what could be down there.

In a photo from 1937, we saw a parking garage that was located on street level. Prior to that, a filling station called the lot home.

"It's a shame if they don't take the time to open them up," Gonzalez said. "Just to let us know what was in there. Because you never know."

Unfortunately, it doesn't seem like we will know what is behind mystery door No. 56.

We haven't heard back from the property owners but construction crews say the project trudges on.

The spot will now become a parking lot; concrete is set to be poured in August.