If you are walking along the Fondamenta Savorgnan (it is on the train station side of the Cannaregio Canal), perhaps on your way to the Ristorante Casa Bonita, you could easily drift right past an interesting part of the history of Cannaregio.
Here is the entry from the fondamenta to the residential area built where there used to be a large factory producing matches (Saffa: Società Anonima Fabbriche Fiammiferi e Affini). The factory operated until the 1950s, and the residential construction began in the 1980s.
A few remnants of the factory can be seen when you walk into the area.
In the Campo del Bagolaro, a water well has been constructed, as an echo of the past. I wonder if those bricks were recycled from the demolished factory?
If you do decide to walk through here, you can have a look at the public park (Parco Savorgnan), and emerge near the Ponte delle Guglie or into Campo San Geremia.