On the corner of 6th and Market Streets is a strange historic monument.

There's a frame that might support a door, but there is no door.

Brick walls that don't actually form complete walls.

There's outdoor fireplaces with flat screen TVs,

yet there's no roof to prevent the fire from going out

or to prevent the TVs from getting wet.

It could be the entrance to the Liberty Bell Center,

a newer home for the infamous Bell that opened in 2003.

Philadelphiaans have told me they've passed this floating doorway without a clue about its significance.

That's not unusual, rushing to work, racing to catch a train or grabbing a drink with friends.

For some, Independence National Park, the Home of Independence Hall, the National Constitution

Center, a freestanding framework of Ben Franklin's house,

and so much more, really just blends into the background.

To understand this monument, we must step back in time to the 1760s when Mary Masters, widow of successful

Philadelphia Merchant and former Mayor William Masters, left their home close

to the docks along the Delaware River and bought a parcel of land in what was known as the Middle Ward.

Now remember Philadelphia was much smaller in the 1700s.

Although those locations were only a few blocks from one another, in a port city moving

away from the river, well it was like moving

across town. A single woman bought land, built her own house. That's a very modern prospect

during a time when women had so few rights, but there were people with even

less rights than a rich former mayor's widow, enslaved people.

...