Time Out says
Don a mask, rent a grand costume and participate in Europe’s most famous and elaborate pre-Lenten carnival festivities.
Almost every city in Italy celebrates Carnevale—the equivalent of Mardi Gras—in the two weeks leading up to Ash Wednesday, but no place does it with the pomp and pageantry of Venice. You’ll find costumed revelers heading to and from boat parades, street fairs and formal balls, and the atmosphere in the city is festive and a tad mischievous. The action centers around Piazza San Marco, but there are events in every sestiere. Carnevale dates vary from year to year, depending on the timing of Easter.
Time Out tip: Do Carnevale up right by buying a handmade mask from one of Venice’s dwindling number of authentic mask-making workshops—try Ca’ Macana or Ca’ del Sol for the real deal.
Attend a Costume Ball: For over-the-top glamour with a touch of Eyes Wide Shut
Basilica San Marco: For Ash Wednesday services and post-festival atonement
Hotel Monaco Restaurant: For an uber-fancy meal, right on the Grand Canal