New York City is reaching a tipping point, architecturally. The city has the chance to go the way of London and Paris, where carefully chosen bits of contemporary architecture enliven an urban fabric that remains largely intact, or the way of Shanghai and Dubai, where relentless repetition of glass facades leads to a numbing sameness.

Several recent developments suggest that New York, for all its attention to the built environment—and 12 years of a design-savvy administration—is choosing the latter approach, permitting continuous walls of glass to erase the city’s history and leave its citizens with little to reflect on but reflections.

The place to see this happening most vividly is Astor Place, in Greenwich Village, where a new building by Fumihiko Maki is nearing completion. Maki, also the architect of Tower Four at the World Trade Center, is known for the taut elegance of his glass skins, and at Astor Place he has delivered just that: the free standing building is completely covered in dark glass, causing one designer whose opinion I asked to reply, “Is that a building? I thought it was a pavilion for a Plexiglas convention.” Entirely lacking in detail—unless you count a few metal fins and subtle variations in the size and color of the panes—the building offers nothing of human scale, and in a part of the city where humanity is at its most resplendent. For most of the building’s perimeter, the grayish glass continues right down to the ground.

Combined with several other recent developments, it may be the last straw for Astor Place and the adjoining Cooper Square.

Flanking Astor Place are a couple of 19th century landmarks, including the Second Empire-style bank building at 7th Street and 3rd Avenue, which is largely intact, right up to its spectacular mansard roof, after more than 150 years, and Cooper Union’s Foundation Building, a muscular brownstone edifice that hasn’t changed substantially since Lincoln spoke in its Great Hall in 1860. And then there’s the handsome Wanamaker’s department store building by Daniel Burnham (1905), a palazzo so self-assured that even Kmart signs can’t undermine it. With so much of the past firmly established, the area could handle a little contemporary architecture—even welcome it, as the city’s history continues to unfold. Indeed, when the Sculpture for Living, a condo tower designed by Gwathmey Siegel Architects, opened in 2005, it was widely ridiculed, but it wasn’t sufficient to destroy the specialness of Astor Place. Neither was the arrival of the Cooper Square Hotel, an overly-busy milky-glass tower by Carlos Zapata. The next big arrival, the classroom building at 41 Cooper Square by Pritzker Prize winner Thom Mayne, is so powerful, architecturally, it actually enhanced the sense of place—something contemporary architecture, like any architecture at its best, can do.

But then came two disasters. First was the demolition last year of a modest brick house, at 35 Cooper Square, which served as a kind of buffer between the Zapata and Mayne buildings. Built in 1825 by a descendant of Peter Stuyvesant, with Federal-style detailing, it had an importance, in tying the neighborhood to its past, far out of proportion to its size. It will soon be replaced by a nine-story dormitory building.

Next came the Maki building, on land leased by Cooper Union to a private developer, Edward Minskoff. (The school, facing financial difficulties, announced last week that it will begin charging undergraduate tuition.) No one laments the loss of the beige brick building Minskoff tore down, yet beige brick was a more thoughtful choice for the location than Maki’s Mylar-like facade. Perhaps the interiors of the new 51 Astor Place will be spectacular—Maki created a great building for MIT’s Media Lab—but 99 percent of New Yorkers will never get inside. And what they’ll see outside is something that seems almost to mock the history of the area, by reflecting the earlier buildings without adding anything to the mix. People come to cities for variety and stimulation; asking them to love a blank glass box is like asking a pet lover to adopt a shiny Jeff Koons dog.

It is happening in other parts of Manhattan, including Broadway and 57th Street, where the recladding of the magnificent 1928 building by Shreve and Lamb at 1775 Broadway, now called 3 Columbus Circle, was a huge loss for the city. Meanwhile, the city is preparing to “upzone” parts of the business district around Grand Central Station, which would encourage glass-and-steel behemoths in place of many of the existing brick and stone office buildings. And it is pushing the development of a giant office park over the Hudson Yards—which William Menking, editor of the Architect’s Newspaper, described as “likely to be the most corporatized landscape this city has ever seen.” At the same time, it is also allowing NYU to fill in huge parts of Greenwich Village south of Washington Square Park with what, in current renderings, are huge glass edifices.

Of course some of New York’s best buildings are glass; the startlingly beautiful Seagram Building is at the top of nearly every list of architectural masterpieces. But even Mies van der Rohe, the progenitor of the glass-skinned building, was profoundly influenced by context. Would he ever have built Seagram the way he did if the surrounding structures had been glass towers, rather than the stolid masonry buildings that flanked it at the time? Unlikely. Phyllis Lambert, who selected Mies for Seagram, and struggled to get it built to his specifications, has also worked much of her life to save the historic limestone facades of her native Montreal from the onslaught of mediocre Mies-inspired buildings. The point is that it takes both old and new, working in concert, to keep a city from becoming a suburban office park.

This isn’t a screed against contemporary architecture. If the trend toward placing featureless glass boxes in pedestrian-heavy spots like Astor Place continues, it is the reputation of contemporary architecture that will suffer most.

But the real concern is New York City’s future. When deciding what to preserve, the city's Landmarks Preservation Commission should think of some buildings—like the house on Cooper Square—as buffers, essential bits of context that allow architectural experimentation to proceed without annihilating context. And in deciding what can be built, the city should realize that while the size and shape of buildings is important (and hence the subject of much of the zoning code), what those buildings are covered in may matter at least as much. Glass has its place, but maybe not Astor Place. Shiny surfaces offer nothing but reflections, and New Yorkers deserve a bit more to look at than themselves.