It looks like a little harbour tucked behind the Procuratie Vecchie, and that is exactly what it is: the Bacino Orseolo is the gondola stazio (a licensed gondola rank) closest to St Mark’s Square. Stop on the bridge and look at the water crowded with black prows: this crescent is not a relic of medieval Venice, but a great 19th-century cut into the fabric of the city.