Driving down I83 towards Baltimore, just past the Northern Parkway exits, you might note construction work to the right of the roadbed where laborers are installing additional track for the light rail system. Just beyond the construction, on wooded land now belonging to Baltimore City’s Cylburn Arboretum, a worn stone wall snakes through the trees. I wonder about it each time I pass. Who built it? For what purpose? It might have been built to contain grazing livestock, or perhaps the land had once been cleared for farmland and that the walls, like those in Ireland, are built of stones uncovered by the plow. I wonder about those who constructed it – someone, perhaps an ancestor of yours or mine – building their life in a new place, remaking their piece of America. I am intrigued because that old stone wall seems to be all that is left of a long-ago farm. I am reminded once again how dense the layers of history are in Baltimore. There are large reminders of the past to be sure – monuments, institutions and well-known facts and stories — but there are also unknown pieces, such as the fragments of this wall and its connecting human story that we might never know.