If you look closely at the lower left of the yellow building in the photo below, you'll see the exposed stone from the original structure. Many older houses leave that peek into the past for all to see. Here's the view of the strip of sky above me, sandwiched by the buildings in the alley:
It still amazes me that people walk these streets every day and don't pause to think about the history that surrounds them. For Italians, 300-year-old buildings are simply part of the landscape.