Alan Mays' photos with the keyword: fortifications

Handwritten note on the back of this real photo postcard: "A study in hand bags." I thought at first that this might be Fort McHenry in Baltimore, Maryland, but I haven't been able to confirm it. Unfortunately, I can't make out any of the inscription on the plaque that's bolted to the side of the brickwork. Does anyone recognize the location? Can anyone identify the type of fortification structure or the kinds of artillery?