For history & culture, Ca' d'Oro (Galleria Franchetti) delivers.
The 'House of Gold' is the most exuberant Venetian Gothic facade on the Grand Canal; inside, the Galleria Franchetti shows Mantegna's 'St Sebastian', sculpture and a beautiful mosaic-floored portego open to the water. The catch: the collection is modest in size for the ticket, much of the original gilding is long gone, and the best view of the famous facade is actually from the opposite bank or a vaporetto.