For beauty & photography, St Mark's Basilica delivers.
Step inside and 8,000 square metres of gold-ground mosaic close over you like the inside of a jewel box — there is nothing else in Europe quite like it. The catch: the free nave queue snakes across the square, you shuffle through in a roped lane in minutes, and the dim light hides the ceiling unless you pay extra for the illumination hours or the Pala d'Oro and upstairs museum.