The memorial at ground zero will be a teeming grove of trees above two deep reflecting pools within the outlines of the twin towers.
At least that was the initial concept. For though the Lower Manhattan Development Corporation yesterday announced the winner of the competition to memorialize those slain at the World Trade Center on Sept. 11, 2001, and Feb. 26, 1993, it delayed a complete description of the design and its image, as well as access to its creators, until a high-profile unveiling planned for next week.
It took that step, the development corporation said, because the winning entry - Reflecting Absence by Michael Arad and Peter Walker - has undergone ``significant'' changes since its initial version was revealed in November, according to Kevin M. Rampe, the development corporation president.
The memorial jury of 13 had requested so many revisions and enhancements during its six weeks of deliberations that it required a new set of models and substantially different drawings. The selection from eight finalists' designs was made on Monday night.
The plan was something of a dark horse, edging out two other designs considered informal semifinalists last week: Passages of Light: the Memorial Cloud; and Garden of Lights. Individual jury members, when called for comment, declined to talk on the record about the selection process, saying that the development corporation had instructed them not to speak to reporters.
A written statement from the jury's chairman, Vartan Gregorian, president of the Carnegie Corporation of New York, said the winning design ``has made the gaping voids left by the towers' destruction the primary symbol of loss,'' resulting in ``a memorial that expresses both the incalculable loss of life and its regeneration.''
Some of the first reaction was positive. ``This is a bold, brave selection by the jury,'' said Frederic Schwartz, a Manhattan architect who was a principal member of a team of finalists in the earlier master plan competition.
The memorial design ``will focus the discussion of the historical meaning of the sacred site,'' he added, ``and its emptiness will be filled by nature, by the sounds of our city, and people.''
Victims' families had varying reactions to the announcement. ``The 1993 families are very happy to be included, replacing the memorial that was destroyed in 2001,'' said Michael Macko, whose father, William Macko, 57, N.J., was one of six people killed on Feb. 26, 1993, when a truck bomb detonated in the parking garage of the north tower.
He added: ``I had some reservations about each of the memorial finalists, but I felt that if they selected any one of the eight, I would be happy.''
But Anthony Gardner, a spokesman for the Coalition of 9/11 Families, said that ``we are extremely disappointed that they went ahead and chose a design despite all of the concerns that have been expressed by the families and the public.''
Mr. Gardner, whose brother, Harvey Joseph Gardner III, died in the north tower, added: ``I think it doesn't matter what the winning design is, the finalists are all the same: they don't incorporate any of the trade center artifacts that are important to the families. I think it's time for another competition.''
The announcement followed weeks of contentious debate in a city whose citizenry quickly scrutinized the eight finalists' plans. The discussion underscored the difficulty of choosing one from the total of 5,201 entrants in the competition for a memorial that would encompass heroic sacrifice and unfathomable loss.
Yesterday, Mayor Michael R. Bloomberg praised the jurors for ``working tirelessly,'' adding that ``I agree with their selection.'' Gov. George E. Pataki said he looked forward to the formal unveiling of the design.
Appointed in April, the jurors - who included Maya Lin, the designer of the Vietnam Veterans Memorial - came under intense pressure after the eight finalists were announced on Nov. 19.
Critics savaged what they saw as the designs' impracticability, their sameness and their generic lack of connection to the specifics of the attack and the city of New York.
Victims' family groups decried what they saw as a failure to provide access to the towers' footprints and a near-exclusion of iconic trade center artifacts that would exemplify the horror. They also expressed anger at what they called a dearth of accommodations for families' large anniversary gatherings.
But Mayor Bloomberg defended the deliberations. ``You're not going to please everybody, I am sure,'' he said yesterday. ``But we put together a process. We said, `Let this committee of distinguished people from a variety of backgrounds and interests go work together and pick something.'''
One of the significant changes to the Arad plan was the addition of Mr. Walker, a former chairman of the Landscape Architecture Department of the Graduate School of Design at Harvard University, who runs his own architecture firm.
Mr. Arad, an architect with the New York City Housing Authority, issued a statement saying he was ``overwhelmed by the news that the jury has selected my design.'' Mayor Bloomberg said he was proud that Mr. Arad is a city employee.
The jurors deliberated for nearly 12 hours on Monday at Gracie Mansion, after the three semifinalist teams made their last presentations to the jury in person. ``It was respectful and collegial,'' said a person present at the discussions, ``and every member made a vital contribution.''
People who knew of the deliberations said jurors had questioned the starkness of the original landscaping and suggested that Mr. Arad collaborate with a design architect, but did not suggest one. The plan's original 100-foot-tall white pine trees, they said, have yielded to another configuration.
They also said that the amended memorial would now allow access to the north tower footprints at bedrock, and would expose part of the now-legendary concrete wall surrounding the site.
The greatest single difference between Mr. Arad's vision for the site and that of Daniel Libeskind, the master site planner, was a barrierlike cultural building along West Street that has already been removed from the evolving memorial plan, according to a person with knowledge of the jury's deliberations.
Last night, as evening descended on the Winter Garden of the World Financial Center moments after the winner was announced, visitors stood before the model of the original Reflecting Absence. Richard Stucki, 36, an architect who lives in Astoria, Queens, allowed as how he had doubts about ``water in the footprints,'' he said, because ``Water is the enemy. You try to keep it out.''
Indeed, yesterday's announcement may, in the end, have been just the beginning of another process. ``I applaud the jury for its perseverance,'' said Mr. Schwartz, the architect, ``but I also urge them to continue their mission by protecting the designers and the clarity of their vision.''