No city in the modern world has exerted a stronger hold on our attention than Berlin, a place that was transformed in just a few hellish years from the capital of an unspeakable regime to the symbol of a divided country, a divided Europe, a divided world.

An exhibition devoted to this fascinating city opened yesterday and continues through March 1 at the Martin Luther King Library. The exhibition, a rather straightforward package of photo panels put together by the government and the construction unions of West Berlin, hardly does justice to the historical amplitude of the theme.

Still, no show has ever been given a more hauntingly ambiguous title -- "Berlin: A City in Search of Its Future." The implied question in the title is unanswerable. The unremitting reality of the city, for visitors and residents alike, is isolation and division.

One can drive unimpeded along the autobahn in West Berlin for nearly an hour, and many Berliners do, in their fast cars. One can stroll for hours in forests -- one-third of the city is kept green and free of development -- and one can even sit in cafe's with picturesque views of farms.

In the end, though, there is no escaping the wall, the mean physical embodiment of division, erected by the soldiers and factory workers of the German Democratic Republic 21 years ago. It stops the fast cars and mars the views. It keeps the citizens of the German Democratic Republic in their place. It has become "grotesquely normal," in the apt description of the New Yorker's Jane Kramer, cutting the city in half "like a jagged line drawn by a demented giant."

The business of rebuilding cities from the rubble of war became the norm in the rest of Germany. In West Berlin there was something heroic about the process, begun with the drone of Allied supply planes in the background, during the tense, exhilarating months of the Berlin blockade. Women did much of the hard labor involved in that job; later the rebuilding was fueled by the West German economic miracle.

West Berlin, one-half of one of the most ravaged cities in Europe, became one of the most stupendously rebuilt cities in the world. Great modern architects worked there: Le Corbusier and, more poignantly, Walter Gropius and Mies van der Rohe, two German architects who helped invent modern architecture during the brief, tumultuous years of the Weimar Republic. Vast modern housing projects replaced the rubble. They also replaced -- and this the exhibition shows very well -- the flattened architectural glories of Berlin before the war.

Much was lost in the forced change, but there is no doubt that some of the edgy vitality of present-day West Berlin is due to this history, and to the destroyed but remembered past -- the creative Weimar years and the huge industrialization of the 19th century, accompanied by enormous neoclassical building projects as well as clashing social upheaval. This is when Berlin underwent its first transformation from provincial capital to great city.

In numbingly dull prose but pictures that sometimes bring the theme to life, the exhibition traces the history of a city. It says very little about Nazi years and very little about the wall, which nonetheless hover in the mind. No one can say for sure what will be the future of Berlin, but no one can easily forget the question, either.