The Basilica di San Marco is one of the finest Byzantine buildings in the world, a glittering accumulation of marble, mosaic, and gilded decoration that took centuries to assemble and still overwhelms at first sight. The current building dates mainly from the 11th century, though building and embellishment continued for several hundred years after that.
The facade is a palimpsest of Venetian history — Byzantine arches, Gothic crenellations, and Renaissance panels jostle for space with columns plundered from all over the Mediterranean world. Inside, the floor tilts and undulates like a stone sea, and the gold mosaics covering some 8,000 square metres of ceiling produce a kind of perpetual twilight. The treasury holds an extraordinary collection of Byzantine goldwork, much of it taken from Constantinople in 1204.
Arrive before opening time (8 am) to avoid the worst queues. Entry to the basilica itself is free; the museum and treasury charge separately. Pre-booking is available and sensible in peak season. Photography of the mosaics is allowed; tripods are not.