Venice

In downtown Boston, the street that starts at the Globe Corner Bookstore and runs past Post Office Square and ends near the Aquarium is called Water Street. In Venice, every street is called water street.

It is a jaw-dropping experience every time. Walk out of the train station and you're at the waterfront. No noise from cars or trucks, just the sound of water, boat engines, and the jibberjabber of people.

Unlike Bologna, which gets a few tourists but is largely off the beaten path, Venice is chock full of visitors. 95% of them manage to stay on the well-trodden trail between the train station and St Mark's (the place with all the pigeons, winged and otherwise). That tourist trail is marked by cairn after cairn of souvenir stands and gross-looking restaurants. Take any side street, though, and you're back in Italy.

This is a perfect city to explore on foot. You will get lost frequently -- the little alleys twist and turn so much that trying to get your bearings is useless -- but you can't really get too far astray without getting wet. And many of those twisty alleys wind up in a lovely little square, where you can rest for a while over a coffee or vino rosso or gelato and watch the Venetians parade by and the ragazzi play soccer.

Seriously, if you only visit one city in Europe, it ought to be Venice, maybe. On second thought, it's stupid to visit only one city in Europe.