Basilica San Marco
Watch your step as you walk with the crowds through the front doors, years of flooding have made the mosaic floor a little undulating in places. You can go further into the basilica and on to the museum rooms for a fee or just admire the ceiling frescos and mind-boggling mosaics, dedicated to the city's patron Saint Anthony, whose remains are interred under the altar (1200yrs and 3 fires later).