--with Peter Vanderwarker

Most of us probably assume that Faneuil Hall Marketplace is a reasonably honest restoration of a great historic work of architecture. But as these before-and-after photographs prove, that's not quite the truth.

In both views, we're looking along North Market Street at one of the three rows of buildings that make up this nationally famous "festival marketplace" (also known, confusingly, as Quincy Market). The markets were built in 1826 and functioned for a century and a half as Boston's wholesale food center. In the 1970s, after the wholesalers moved out, the city "restored" the old buildings.

But the architects didn't merely restore. They also demolished and rebuilt. They were purists who wanted to strip away the accumulated changes of time. They wished to re-create the markets as they had looked, presumably, in 1826. That meant tearing down much of the complex and rebuilding it, using new granite cut from the original quarry.

When the "restoration" was complete, the developer James Rouse and the architect Benjamin Thompson filled the markets with the lively mix of food stalls and boutiques that we've come to know. The mix was more pungent once than it is now. National chain stores, for example, were banned in the early years.

The real fascination of these photos lies in the way they measure a change in taste. Nobody today would be likely to perform so violent an architectural restoration. Preservationists have become more sophisticated. They prefer to retain the evidence of change over time, rather than obliterate it. A building can thus become a rich living history, not merely a memorial to the moment in which it was built.

The Boston author Kevin Lynch put it best: "There is a pleasure in detecting the various layers of successive occupation of the city as they fade into the past -- and then in finding a few fragments whose origins are remote and inscrutable, whose meanings lurk beneath their shapes, like dim fish in dark water."

In the 1954 photo, the original buildings lurk beneath a coral reef of accumulated change. They possess, indeed, the mysterious fascination of dim fish in dark water.