LANDOWNE, Pa. (WPVI) -- One would never guess the rich history behind the walls or underneath the basement of a white, Colonial-style home in Lansdowne, Pennsylvania."Yeah it's kind of wild, something I've never seen before," said Mike Knoll, mason. "I've been doing this 20 years, and I've never seen anything like it.""Something was definitely down there," said Alex Poulous, homeowner.It all started with a crack."We noticed that there was some cracks in the walls in the basement that were getting worse," said Jerry Sanders, tenant.Poulous called in Baldwin Masonry , and they quickly worked to put up columns to support the ceiling.In that process, they tore a hole in the basement floor. That's when they literally got a peak into what appears to be a piece of American history."Probably another room on the other side of this wall," said Knoll.Local experts believe it was one of many secret stops along the Underground Railroad. It's where runaway slaves were hidden in their quest for freedom."The rooms would be hidden. It would be behind something, under something, blocked off somehow so it's very likely," said Upper Darby Public Libraries Director Nancy Hallowell.Poulous' parents bought the home back in the early '70s. They'd heard rumors about this, but never imagined it could possibly be true."The neighbor actually told my dad in the past, 'I think there's a basement under your basement,' " said Poulous. "A little bit in shock that we lived here for so many years and never knew that this existed."Now they have what may well be proof, and quite a story to tell."Never forget this job," said Knoll.Poulous tells us she has no plans of covering the hole up. In fact, she wants to see what else is down there.Meanwhile, historians tell us there are many stops or stations like this in the area. Most homeowners just don't know about it.