Venice's set pieces cluster within ten minutes of San Marco, but the city improves the further you walk from them, into Castello, Cannaregio and out to the lagoon islands.
Basilica di San Marco
The mosaic interior is the reason to go, and the Pala d'Oro altarpiece and the museum with the Loggia dei Cavalli horses are ticketed separately from basilica entry. Entry is by timed slot, dress code is enforced, and large bags have to be left at the free deposit round the corner before you join the queue.
Palazzo Ducale
The Doge's Palace on the Piazzetta, run by the city's museum foundation, with the council chambers, the armoury and the Bridge of Sighs. The ticket is the St Mark's Square Museums ticket, so it also covers the Museo Correr, the Museo Archeologico Nazionale and the Marciana library rooms across the square.
Peggy Guggenheim Collection
Twentieth-century modernism in Peggy Guggenheim's own unfinished palazzo on the Grand Canal, with a sculpture garden and a canal-side terrace. Open daily 10am to 6pm, closed Tuesdays and 25 December, with the ticket desk closing at 5pm.
Scuola Grande di San Rocco
Over sixty Tintoretto canvases still in the rooms they were painted for, in the confraternity building beside the Frari. Open 9:30am to 5:30pm with the ticket office closing at 5pm; 8 euro standard and 6 euro reduced, and the adjoining church has been closed for restoration.
Murano, Burano and Torcello
Vaporetto line 12 from Fondamente Nove runs out to Burano and Torcello, which is a half-day at minimum; Murano is much closer and served by several lines. If you are island-hopping, a timed ACTV travel pass costs less than buying single fares.