Venice, Italy — Surely it will sound like sacrilege to propose that Venice’s Piazza San Marco, the “drawing-room of Europe,” as Napoleon famously called it, could stand improvement. But Americans abroad have never been known for their modesty, and it is in that spirit that I offer my services to the Most Serene Republic, with a suggestion that could have far-reaching urbanistic implications for its famous civic center.

Before coming to Venice recently, I was in Rome, where I was struck by a recurring weakness in some of the grandest public spaces in that city and elsewhere in Europe.

Rome’s most successful piazza is the square in front of the Pantheon. Perfectly scaled, it is graced not only with its incomparable ancient temple, but also with a secondary focal point in Giacomo della Porta’s charming fountain. Surrounded by ice-cream parlors, restaurants, and cafés, every part of this well-lit square is charged with life at all hours, though rarely to a clamorous degree.

But consider the famed Piazza di Spagna, or Spanish Steps. Besides the coup de théâtre represented by the steps themselves and by the Barcaccia fountain at their base, this square has no cafés or restaurants that extend its vital energy beyond those two points. Instead, its energy is considerably depleted by the time you reach the College of the Propaganda Fide at one end, and it is all but nonexistent at the other.

Many another famous European square fares no better. Rome’s Campo dei Fiori is almost always desolate, and Madrid’s Plaza Mayor, though surely imposing, is severely underused. Meanwhile, the only thing that adds interest to Paris’s otherwise lovely Place de la Concorde is the imminent threat that one will be flattened by oncoming traffic.

Which brings us back to the Piazza San Marco. For more than 1,000 years, its beauty has been beyond dispute. Surrounded by the Basilica, Campanile, and Doge’s Palace to the east, Mauro Codussi’s Procuratie Vecchie to the north, Baldassare Longhena’s Procuratie Nuove to the south, and the so-called Ala Napoleonica to the west, the Piazza San Marco has changed little in appearance in more than 300 years.

But you have only to watch how both natives and tourists inhabit the space to see that something is very wrong. In addition to the majority of visitors, who collect around the flagpoles beside the Basilica, there are swarms of subsidiary energy in the square’s two main cafés, Florian’s to the south and Quadri’s to the north — with their orchestras playing and the public waltzing around them. But in the rest of the square, especially at the western end, almost nothing is stirring. And at the very center of the square, at its most crucial point, all energy suddenly evaporates and a distinct spatial flaccidity sets in. That is because, if the truth be told, the piazza’s enormous size outpaces any likely function.

My proposal for remedying this deficiency is to place something big, a sculpture, for example, at the center of the square. It would immediately give scale and focus to every other part of the square and provide a homing point for every person who enters it. The problem, of course, is to find a sculpture that could possibly be equal to such a task.

Well, it happens that there is one sculpture in the world, which, in its excellence, may well surpass any other sculpture ever made and which — more crucially — was created precisely to stand at the very center of the Piazza San Marco. I refer to the Colleoni Monument, created by Andrea del Verrocchio and cast, a year after his death, in 1488.

Bartolomeo Colleoni, perhaps the most effective and honorable of those condottieri who traversed Italy in the 1400s, left money in his will so that an equestrian monument could be raised to him in San Marco’s. But through that conniving cleverness that often characterized the actions of the Venetian senate, it decided to erect the statue in front of the Ospedale San Marco — on the absurd grounds that Colleoni had not specified which San Marco he meant.

But the joke was ultimately on the senate, and on every subsequent generation of Venetians. In terms of power and sheer moral force, nothing can come close to the awesome energy of this mounted knight, with his craggy face and demonic eyes. Both he and his mount, in their merging of controlled violence and classical balance, seem to have issued forth from the gates of hell into the light of righteousness. Whatever the truth of Venice’s role in history, it could never ennoble itself more than by associating itself with the sublime spirit of Verrocchio’s masterpiece.

And yet, most visitors to Venice never see the Colleoni Monument, which rises upon a lofty base of pink granite that is scarcely less beautiful than the sculpture itself. That is because it is tucked away beside the Church of San Giovanni e Paolo, which is so successfully hidden in a labyrinthine warren of backstreets that even the natives often have trouble finding it. Transferred to the place for which it was originally intended, this sculpture would at last receive the recognition it deserves, and the Piazza San Marco would achieve the urbanistic coherence that, for the past millennium, has eluded it.

Before the actual transfer occurred, perhaps a simulacrum of the monument could be raised in the center of the square. Even then the effect would be so instantly compelling, I believe, that there would be little resistance to the idea of placing the sculpture there permanently.