We are just about to arrive at the Piazza San Marco on the first evening. On the right, just out of view but indicated by the yellow ferry, is the (or perhaps "a") Pontile ACTV, one of the docks of the local public transport service. Ferries, naturally.

I had a bit of a hard time placing this until I realised... trees. There are trees there. Trees are not a common sight in Venezia, so I was able to connect those dots to the Giardini Reali, the Royal Gardens. The small building on the right of the canal is the Palazzina Selva, whose role I'm not quite sure of. The canal itself is not one of the ones that criss-cross the island; it runs along the side and around the back of the gardens, then stops; it partially encloses them almost like a moat.