In this highly litigious city of ours, nothing is ever certain. The best laid plans can be held up indefinitely in the courts, and where government is involved, one man, usually Sheldon Silver, can countermand a hundred other rulings, as he did regarding the ill-fated Jets Stadium on the far West Side and as he threatens to do again with the renovation of Penn Station.

The one exception to this fecklessness is the fait accompli, that point from which there is no turning back. Go to Lincoln Center these days, and you will find that Milstein Plaza, which had been suspended across West 65th for almost 40 years, has completely vanished, as part of Lincoln Center’s massive modernization effort, led by the architectural firm of Diller Scofidio + Renfro.

Until a few weeks ago, Milstein Plaza’s sluggish travertine mass covered almost half of 65th Street, from Broadway to Amsterdam Avenue, in perpetual night. On one side it hid the entrance to a massive garage under the Metropolitan Opera, on the other, the entrance of the Peter Sharp Theatre. But the garage rather than the theater determined the spirit of the place, and the garage itself seemed tolerable and appropriate only in virtue of that sense of dank sleaziness that marked the unadorned underside of the plaza. Like a toxic trace, the malign effects had spread far beyond the entrance of the garage, making 65th Street a series of inglorious back doors to the various entities, Juilliard, Avery Fisher and the Performing Arts Library, that had emphatically turned their backs on it. Bracketing these back doors were dull and interminable lengths of masonry. And it did not help matters that, closer to Broadway, the street was flanked by the mediocrity of Max Abramowicz’s Avery Fisher Hall to the south and by the brutalist gracelessness of Pietro Belluschi’s Juilliard School to the north.

Now, with the plaza finally removed, it is a pleasure to see daylight returning to this forlorn street. Suddenly the visions of the architects, which had a pie-in-the-sky quality until a few weeks ago, seem within reach. In Diller Scofidio + Renfro’s conception, the street is to become a destination in itself, equipped with restaurants in a part of the city that, oddly, has far fewer culinary options than you would expect, given the thousands of potential diners who flood the area each evening.

At the same time, the entrances to the various venues, especially the Samuel B. and David Rose Building, will be made more emphatic, such as to seem consequential in their own right. In the process, the heavy travertine masonry will give way to transparent facades at street level for the Chamber Music Society and the Film Society of Lincoln Center, as well as the School of American Ballet, among others institutions.

The Milstein Plaza itself, which served as a kind of bridge across the 65th Street, as well as a plaza in its own right, will be replaced by a frail glassy foot-bridge whose very fragility will doubtless serve, visually as well as functionally, as a post-modern riposte to the modernist heaviness of what was there before.

Perhaps most striking of all, Alice Tully Hall, at the Eastern end of Belluschi’s Juilliard building, will be entirely reconceived in highly angular deconstructivist fashion, as a bellicose protrusion into Broadway. In the context of so much change for the better, there is something joyous in seeing all the chaos, all the excavations, even the scaffolding that surrounds the area.

But if the realization of this project is still at least a year away, a small but significant modification of the Metropolitan Opera was unveiled just this past week, tucked into the southern corner of the ground floor, facing Lincoln Center’s main plaza. It is perhaps the only important change that the façade of Wallace K. Harrison’s ungainly opera house has sustained since its completion exactly 40 years ago. The new arrival, an art space called Gallery Met, was designed by the young and fashionable Lindy Roy. Its most striking feature is its mirrored exterior, which makes no sense in the context of the larger building, but is dramatic all the same. As for the interior, it is a slightly irregular space, roughly the size of one of Chelsea’s smaller galleries. It flows into the main lobby of the opera house, from which it is divided by two elegantly spare faux marble partitions. Best of all are the terrazzo floors, which are part of the original building, but are here revealed to best effect.

Unfortunately, the art itself is not equal to the space. Guest curator Dodie Kazanjian has chosen, in seemingly formulaic fashion, the usual blue chip artists of the moment (David Salle, John Currin, George Condo, and seven others) none of whom distinguishes himself in fulfilling the assignment, to create a work involving the heroine of one of the operas performed this season at the Met. Still, Lincoln Center, that magnet for vultures of culture, has always aspired to embrace all of the arts, and this new gallery — which replaces an older, subterranean space — is a noteworthy step in that direction.