I work in an old flour mill up against the historic C&O canal here in Georgetown -it is one of my favorite things to see here in the city. Down a level below the street, hidden from most tourist traffic, the canal and adjoining towpath is a great and charming way to get around Georgetown. Most of the path is surrounded by beautiful old stone walls with plants growing between the stones and old industrial buildings converted into architect and lawyer's offices.
the modern atop the old
This old bridge you can see here dates to the early 19th century. I love that the buildings along the canal have windows down to the water level.
Some bridges are old, others are modern, like this one. I marvel at how these old walls can hold buildings on top of them!