Another part of the Berlin I knew is gone.

My wife had an interview appointment for a U.S. visa last Thursday morning, so we rose before dawn and took an eastbound InterCityExpress into the capital. The last time I'd been there was before the opening, in May 2006, of the new main train station, an $850-million, glass-roofed exclamation mark on what used to be the no-man's-land between West and East Berlin. An impressive edifice it is, I sensed, but even a cursory inspection was out of the question because we had to double back west pronto, by commuter train, to Zoologischer Garten Station (Bahnhof Zoo) to take the subway southwest to Berlin-Dahlem, where the consular section of the U.S. Embassy is.

Scheiße. Long-distance trains don't stop at Bahnhof Zoo anymore.

Bahnhof Zoo was West Berlin's main station, its hub, its heart, and the first impression of divided Berlin for generations of Cold War travelers. How many times I disembarked and embarked there, and ate schnitzel and drank beer in the restaurant upstairs! When I arrived in West Berlin in 1977 to study at the Free University, bringing only what I could carry, I got off the train at Bahnhof Zoo, stepped outside, looked around, sniffed the Berliner Luft, set off for a cheap hotel and promptly had my first adventure.

A professional roulette player offered to put me up. Partial to Americans after a visit to the States, he'd overheard me asking directions and recognized my accent. I stayed with him, a regular guy who went to "work" in a tie, until I found a dorm room.

Minus major train traffic, the Bahnhof Zoo neighborhood is dying today. Hoteliers and retailers have taken a body blow. A friend of mine, a Berlin optician who until recently had two shops, gave up the one on Joachimstalerstraße, a short distance from the station.

Reunified Berlin's center of gravity lies in former East Berlin, which included the city's core. The East is the location of the hippest night life, the main museums, city hall, and much of the federal government quarter. The two airports in western Berlin, Tegel and Tempelhof, are being phased out in favor of Schönefeld, which formerly served East Berlin and is now being expanded at a cost of two billion euros.

The U.S. Embassy is also in eastern Berlin, in the building that housed the U.S. Embassy to East Germany. A new, fortress-like embassy building, scheduled to open next spring, is under construction on Pariser Platz, previously in the no-man's-land on the East German side of the Berlin Wall. The consular section of the U.S. Embassy in Berlin, where my wife was expected, used to be the U.S. Mission in West Berlin.

The old mission building is part of a compound, once occupied by Nazi Germany's Luftwaffe, that headquartered the U.S. Army Berlin Brigade. I taught English for a while to German civilians who worked on the military base. This area is where I saw my first tanks. I was chatting in a phone booth on Clay Allee, named after U.S. General Lucius D. Clay, when a distant rumbling gradually became deafening and the ground began to tremble under my feet. I'll never forget how fearsome those beasts looked clanking by.

The troops left Berlin in 1994, and the big American shopping center on Truman Plaza, across Clay Allee from the mission building, was razed. Slinky, gum-chewing GI's no longer make the scene. When we passed Truman Plaza last Thursday, I glimpsed a couple of stinky, cud-chewing camels -- a circus was camped on the grounds.

For all the profound changes in Berlin since German reunification, some things, of course, have stayed pretty much the same. One of them is KaDeWe, short for Kaufhaus des Westens, the classiest department store in Berlin and biggest in continental Europe. It celebrated its 100th anniversary this year. After my wife had successfully negotiated all the security checks and visa requirements at the consular section, we took the subway to KaDeWe, on Wittenbergplatz in western Berlin.

I led her straight to the sixth floor, the gourmet department. Berliners call it the Fress-Etage, or "pig-out floor," since more than 30 sit-down counters beckon among the shelves and stands filled with food and drink. The selection is mind-boggling and mouth-watering: 1,200 kinds of sausage and ham, 400 fine cheeses from France alone, handmade chocolates, delicious flans and petit fours, exquisite tea and coffee blends, great wines and spirits, Nashi pears, pitahayas, guava, oysters, parrot fish, sea urchins, king prawns, venison, moose, wild boar, etc., etc. When I lived in West Berlin, I bought peanut butter there.