You can’t go to Venice and not spend some time in Piazza San Marco (St. Mark’s Square). (You can go to Venice and not ride in a gondola, though!) In many places throughout the city are signs, with arrows, directing you to this square, so it’s actually hard not to find. St. Mark is Venice’s patron saint, and the San Marco Basilica is the most famous church in Venice. Trying to stick to our “one church per city visited” we did go into St. Mark’s Basilica to gawk at the gold mosaics which cover many of the surfaces. Unlike most churches we’ve visited, this one has a distinctly Byzantine flavor, especially inside. This short Rick Steves video of the basilica gives a glimpse inside (no photography allowed for mere tourists). The outside is such a mishmash of various marbles, mosaics, carvings, etc. that the Venetians plundered from their enemies. Rick Steves calls the style Early Ransack.
In 828, two merchants of Venice stole the remains (some of the remains?) of St. Mark (of Gospel-writing fame) from Alexandria since it was believed that he had come to Venice to spread Christianity (although the dates do not match up, it makes a good story, I guess). Mark’s symbol is the winged lion, and there are many examples of this creature throughout the city.
We skipped the Doge’s Palace tour (next to the basilica), but we did see the famous Bridge of Sighs which leads from the Palace to the prison. The prisoners were supposed to have caught their final view of the Grand Canal through the windows on this bridge, give a sigh, and enter their cell where they could only remember the beauty outside.