One of my favorite postcards of Rockport is The Town Turned Upside Down, an early 1940s postcard by Virginia Cleaves Little. (That link takes you to my original post of it.) Now, my talented son Ben Ambrogi has worked some Photoshop magic to fuse parts of that 70-year-old image with the same scene today.
Above, you see the fruits of his labors. Click on it to bring up a much larger version. Note that the reflections in the water show the buildings as they were then, letting you compare them with what is there today.