For Westerners, the center of Berlin suddenly shifted east when the Berlin Wall fell in 1989. The geographic heart of the metropolis still lies in the bohemian neighborhood of Kreuzberg, with its big, loft-like apartments and sometimes raucous night life. But reunification of East and West has meant that the city's spiritual core has returned to Museumsinsel — Museum Island — a spot of land in the Spree River that is home to an array of seminal art museums stuffed with astounding collections. Nearby, the once drab East Berlin neighborhood around Auguststrasse, just a short walk across the river, has metamorphosed into the liveliest contemporary gallery scene in Europe.

I've joined that throng of fans. After a 17-year hiatus, I returned to Berlin to renew old art acquaintances and encounter new ones. Back when Germany was divided, Berlin was a bubble — a fragile space station of contested earthly values, tethered on one side to Washington and on the other side to Moscow. That bubble burst, but the fizz remains.

Freewheeling Weimar liberalism, unspeakable fascist barbarism and the kabuki dance of Cold War posturing — evidence of the city's last century lingers around every street corner. Today a new, not yet fully defined profile is being added. The new Berlin seeks to come to terms with Germany's dark past while building on its better self to emerge as an incomparable cultural capital. The city is in the throes of growing pains, with all the excitement — and anxiety — that assertive urban evolution entails.

For this art critic, surprises were in store. The amazing mix of great historical art museums, ambitious contemporary galleries and eager young artists now flocking here for inexpensive studio space has put Berlin in an enviable, even unrivaled position.

Encompassing 344 square miles, Berlin is a bit like Los Angeles — less a concentrated urban center than a sprawling, multiethnic metropolitan region with urban pockets. (At about 350 years old, it's also Europe's youngest major city.)

Public transportation is excellent, taxis are abundant if not inexpensive, bicycles are common, and a car is helpful. Boats ply 120 miles of urban waterways.

From my hotel, the sleekly efficient Radisson SAS in Mitte, Museum Island and the galleries around Auguststrasse can be reached on foot.

History's collectors

To understand Berlin's museums, it's important to know two things. First, Germans have been voracious collectors since the 17th century, when the princely enterprise of art collecting reached its first maturity all over Europe. Second, Germans were among the first to view treasures of the past in what we now regard as a modern way. By the 19th century, they had begun to invent the discipline of art history, as a way to organize the booty.

The scope of their ambition is nowhere more apparent than in the Pergamon Museum, which opened in 1930 as the newest and final attraction on Museum Island, home to five museums and declared a UNESCO World Heritage site in 1999. It's now the city's most popular tourist destination, with more than 850,000 annual visitors, and houses classical antiquities, ancient Near Eastern and Islamic art.

The big draws are the monumental architectural ensembles — ancient buildings reconstructed inside the museum.

There's the Pergamon Altar from 2nd century BC Greece, with its magnificent Hellenistic frieze depicting a fearsome battle between gods and giants; the Roman Market Gate of Miletus, now partly obscured by scaffolding during restoration; and Babylon's cobalt blue Ishtar Gate, with its stately procession of animals, both real and mythological.

Museum Island was severely damaged during World War II — strafe marks are still visible on stone walls — and restoration is ongoing. The Bode Museum, with collections of coins, sculpture and Byzantine art, will reopen in 2006; in 2009, the Neues (or New) Museum, after renovation, will house the city's renowned Egyptian collection — including the famous one-eyed bust of Queen Nefertiti.

The spectacular 1876 Alte Nationalgalerie (Old National Gallery) was restored and reopened in 2001. Its rooms and picture bays, lined in gilded paneling and crimson fabric, are devoted to 19th century art. Skylights in the top floor mean that no artificial illumination spoils the viewing of 11 works that span the career of Caspar David Friedrich, the Dresden Romantic genius.

The centerpiece is "Monk by the Sea" (1808-10), showing a tiny, hooded holy man standing at the shore and confronting an immense, darkly luminous void. The painting astounded viewers 200 years ago — and still does. Friedrich portrayed spiritual mystery in the secular guise of the natural world, an early assertion of a distinctly modern faith.

The first museum on the island

So, in another way, was the Altes Museum (Old Museum), the first of the island's museums. It was built between 1823 and 1830 according to the neoclassical designs of hometown hero Karl Friedrich Schinkel and rebuilt after burning to the ground in 1944.

An elegant cross between an ancient Greek temple and Rome's Pantheon, the Altes now houses extraordinary collections of Cycladic, Greek and Etruscan art, Scythian gold and some Roman art. (Egyptian art, including Nefertiti, will be temporarily housed on the second floor, starting Aug. 13.) The Greek vases are especially fine. No embarrassment intrudes on showing their full range of orgiastic, homoerotic and other playfully salacious painted scenes, which some museums shy away from.

The only problem is the ugly clutter of display cases — clunky glass boxes set atop virtual saw horses — which are low and cause a painful strain on the back.