The twin towers of the World Trade Center should never be rebuilt. When the last of the rubble is cleared, and when the remains of all those fallen New Yorkers have been given their proper blessings and farewell salutes, those 16 mutilated acres should be converted into an oasis of life.

That is, they should become a fitting memorial for the humane values of our civilization. Many people will have visions of what form that memorial should take. Mine is simple: a park.

A park where the children of the 200,000 New Yorkers who live downtown can bring their children on summer days, and watch them ramble among grass and trees.

A park that in winter will be white with falling snow, instead of the carpet of dust and ash that has covered it since the morning of Sept. 11.

A park that contains one simple memorial wall of polished stone, in the style of Maya Lin's Vietnam wall in Washington.

Listing the names of every fireman, policeman and emergency worker, every passenger on those doomed airliners (except the terrorists), and every single human being who died in this greatest of American calamities.

There is much talk about rebuilding the twin towers, and the other damaged buildings, as a display of resolve in the face of terrorism. The emotions of such talk are genuine, and honorable. With enormous respect, I disagree.

One basis for disagreement is practical. The task of reerecting the towers would take about five years, and possibly longer.

It would cost billions. And at the end of that process, much of the space would be unrentable. Very few companies would compete to lease the upper floors. Few human beings would ever want to work on those floors, no matter how many reassurances they are given about the building's new invulnerability, and the vastly increased security measures forged in the aftermath of the disaster.

What's more, the rebuilt twin towers would remain permanent targets for every form of terrorism, foreign and domestic. The terrorists who killed six people and injured more than a thousand in the 1993 bombing were in prison when the others came from the skies on Sept. 11. Some of these addled killers would be waiting to strike the new towers, in hopes of doubling or tripling the death toll of the innocent.

Many of those God-driven killers are at large right now. More will be created when the Americans start their necessary retaliation. The rationale is primitive and tribal: You kill my sister and I'll kill 10 of your brothers. The fanatic's sense of time is elastic — they can wait 10, 20 years, and when it seems that the threat has vanished, they will strike.

They will almost certainly strike anyway, in ways that we can only imagine. But we should not offer them a convenient, symbolic target.

Vertical vs. Horizontal

There is also something practical to learn from the contrast between the assault on the twin towers and the crash of American Airlines Flight 77 that smashed into the Pentagon. The twin towers were vertical, rising above all the other towers of a vertical city. The Pentagon was horizontal, hugging the ground near the Potomac. More than 5,000 human beings perished at the World Trade Center. At the Pentagon, with all of its own horror, the total was 190.

The real estate developers — many of them honorable, intelligent men and women — should learn from that contrast as they work at replacing the 20 million square feet of office space that has been lost. They must enlist architects and city planners who recognize the now-permanent vulnerability of their high-rise buildings.

They should look at sites in Brooklyn and Queens where shock-proof high-tech complexes can be built that limit damage from explosions, and are able to seal off air that is contaminated by biological weapons. These should have deep escape tunnels, buried telephone cables for communication, access to all forms of mass transit. This kind of decentralized rebuilding might take a decade. This war will last much longer.

There is some talk that the New York skyline, that splendid accident, has been ruined by the fall of the twin towers, and therefore must be replaced. Again, forgive me: I disagree.

There were many of us who thought that those towers — as architecture — had ruined the skyline when they were completed in the early 1970s. I grew up on the slopes of Brooklyn with a clear view of the skyline from the back windows and rooftop of our tenement. That skyline did not include these huge, blunt, flat-topped hunks of steel and glass. Our skyline climbed to elegant spires, reaching for the heavens.

Skyline Shines Bright

On the evening of D-Day, 1944, when I was 9, the whole neighborhood — almost all women, children and old men, because the young men were away at the war — climbed to our rooftops, to gaze out at the extinguished skyline.

It had been dark since Dec. 8, 1941. But now the men of our neighborhood (and many others) were landing at last in Normandy, on their way to destroy Hitler. And then, at the command of Mayor Fiorello LaGuardia, the skyline burst into brilliant, dazzling, triumphant light. And you could hear a roar from all the rooftops of Brooklyn. Until that moment, I had only seen that night scene in movies. And here it was: the astonishing nighttime skyline of New York.

That night on the roof my mother started singing "White Cliffs of Dover" in her light soprano voice, a grieving, defiant counterpoint to those roaring for the lights, and all the others joined her in the song they'd learned from Vera Lynn. "There'll be bluebirds over. ..." And that glittering skyline, rising out of the black harbor and the unseeable rivers, became an image I have carried with me in all my wanderings in foreign lands, across all the years of my life.

The Other Monuments

That skyline was a beautiful thing to see, what Truman Capote later called "a diamond iceberg." No religious lunatic built it, none can destroy it. The Empire State Building is once more the tallest structure in New York. The Woolworth and Chrysler buildings still beckon to each other, uptown and down, call and response, across the streets of Manhattan.

But down there at Ground Zero, I want to see an enduring monument to what we should think of as our greatest structure: freedom. I want it to represent our pluralism, tolerance, and refusal of fanaticism. I'd like to see an oak tree planted in memory of every nationality that died there, carried by government ministers from the soil of their lands. I want a strip of fence welded together from fragments of ruined police cars, fire engines and ambulances.

Most of all, I want to see flowers bloom where so many died. I want to hear children laughing, and ballgames playing on radios, and see old men on benches reading Yeats. I want to hear the rattle of leaves on autumn afternoons. I want to inhale the salt air of the sea. In short, I want enduring proof of our ultimate triumph over those heartless men who say they love God while despising laughter and dancing and human life itself.