One of Europe's charms is its crowded cultural diversity. Open borders and a common currency haven't smoothed many wrinkles. Hop on a train, and before you know it, the language, food, architecture, attitudes and criminal code are different from those at the point of departure.

A trip out of Germany, in any direction, is a reminder of how uptight Germans tend to be. Take hookers, for instance.

My wife and I recently went to Amsterdam. Among the sights she wanted to see were the women in the windows of the city's red-light district. This might seem an odd wish from someone living in Hamburg, where prostitution is also legal, and where women also present their wares for sale in the windows of the red-light district. But she's never seen them in Hamburg because she's not allowed to. The meat display cases there are on a 60-meter-long street called Herbertstrasse, both ends of which are blocked by iron gates with signs saying "Entry for men under 18 and women prohibited." That's not the law. That's an order from the proprietors -- the street is private property. I've escorted some curious women down Herbertstrasse in my time, and you've got to be quick if you don't want to be assaulted. The scantily clad harpies don't take kindly to female scrutiny. At the very least, they bombard trespassers with the most vulgar of curses; and with water, beer, or any number of unpleasant objects.

In laid-back Amsterdam, though, the working women in the windows aren't hidden from anyone's view. They duck away from cameras, understandably, but show no aggression. My wife got an eyeful and satisfied her curiosity.

On the train ride back, the Dutch conductor joked with passengers. He was replaced at the German border, and we were asked to present our passports. "How come?" I wondered. "We haven't left the European Union."

"You're obligated at all times to be able to identify yourselves," the German official responded. His tone was clipped and supercilious. Jawohl, we were in Germany again.