Venice is not a city that you can walk around in at night by the light of the street lamps. The city sleeps when the sun disappears, except near the Grand Canal and St. Marco's Square. In my opinion, there is nothing more romantic than to wander what Napoleon called "the most beautiful room of Europe": The Ducal Palace, the church of San Marco, the Campanile, and The Piazza of San Marco when the sun sets. When you finish your stroll, the perfect ending is to have a coffee or a cocktail at one of the cafes in the square. The most famous are the Quadri and Florian.