For once, this is not a traditional Venetian festival. It is only in recent years that it has become customary for Venetians to leave their homes on New Year's Eve and head to St.Mark's Square to welcome the New Year with a kiss.
Until then, there are various performances on the stage set up there. Finally, the highlight - heralded at midnight by the bells of the Campanile, sealed with a kiss (of course, only among the couples present), and celebrated with a spectacular fireworks display.
Just don't.
Things you definitely don't want to try in Venice.
You should definitely avoid bringing your own fireworks, unless you've already factored the potential €500 fine into your vacation budget. Illegal fireworks are a particular problem in Italy, as various campaigns across the country highlight (whether this actually helps, of course - like so many things in Italy - is another matter entirely).
So Venice finally came up with the commendable idea of organizing a "mass kiss-in" on St. Mark's Square on New Year's Eve. As with so many festivals in Venice, if you want to eat at a restaurant beforehand, it's advisable to make a reservation well in advance!
And, of course, dress warmly - the sea breeze is bitingly cold.