Torcello is the most remote of the easily accessible lagoon islands, an hour from Venice by vaporetto. Once it was the oldest settled island in the lagoon, a thriving Byzantine city that predates Venice itself. Now it is almost entirely abandoned — a flat, reedy island with a handful of buildings, a few market gardens, and a cathedral that predates most of what you will see in Venice.
The Cathedral of Santa Maria Assunta, founded in 639 and rebuilt in the 11th century, contains the most important early medieval mosaics in northern Italy — a Byzantine Last Judgment on the west wall and a serene golden-ground Madonna in the apse. The solitude of the island and the age of the building, standing alone in an empty field with the lagoon on all sides, is remarkable. Hemingway drank at the Locanda Cipriani here; it still operates as a restaurant and hotel. Come on a weekday when the tour groups have gone.