Some of the world's top architects are helping New York to recover from the devastation of last year's September 11 attacks. DAVID USBORNE looks at their visions.
The thrill and promise of urban rebirth and civic imagination returned to lower Manhattan this week as seven teams of architects from around the world unveiled startling visions of what could rise from the devastation wrought by terrorists.
Their brief was to fill the space left by the Twin Towers, destroyed in the terrorist attacks of September 11 last year.
And their nine plans share a common theme of honouring those who died in the attacks with memorials and open spaces.
But otherwise, they diverge dramatically. One envisages a floating park with 2800 lights representing the victims.
Others feature structures that would be the highest in the world.
Nearly all incorporate multiple gardens.
Sir Norman Foster, the one British entrant in the competition, presented a dazzling blueprint dominated by "twinned towers", a glass-sheathed and highly sculptural skyscraper that would divide into two parts but "kiss" at three points to create public space and observation decks.
He also incorporated two sunken and lifeless "voids" occupying the canyons left by the original Twin Towers.
The Lower Manhattan Development Corporation (LMDC), created to oversee rebuilding on the 6.5ha site, will spend six weeks looking at the plans and will name a finalist at the end of next month.
Public reaction will be crucial, although plans for open hearings have yet to be fully detailed.
Officials can pick a single winner or a combination of the different designs.
"These are designs not only for our time, but for all time," said LMDC chairman John Whitehead.
"They must transcend the present to speak to our children and to their children ... to send an immortal message."
All the plans have space for memorials. These will be designed separately in a parallel competition.
Four of the plans propose creating the tallest building in the world, outstripping the 110 storeys of the old Twin Towers and topping Malaysia's 452m Petronas Twin Towers.
One includes a 640m skyscraper, and another has a 541m tower topped with a sharp-ended spire.
In one of the most ambitious proposals, a team called Think, led by Italian architect Rafael Vinoly, advocates a soaring pair of circular open lattice-work structures, almost helix-like scaffold-towers, punctuated by public spaces, including performance areas, at different levels.
Another group, United Architects, proposes a massive blue-glass wall of multiple and fluid glass towers - higher than any building now standing - that join at the 60th level to create a single contiguous public space running through all of them.
The image is of a giant and space-age cathedral of glass.
The scope of the plans reflects New Yorkers' desire for buildings that do more than simply replace the lost office and retail space.
An earlier round of plans, unveiled in July, was greeted by public dismay and rejected as boring and inadequate to meet that challenge.
The response prompted the LMDC to hold the competition now nearing completion.
The seven teams were chosen from 407 submissions from around the world. They are from Berlin, London, Amsterdam, Tokyo, New York and Los Angeles.
Their leaders include some of the world's leading architects - Foster, Vinoly, Richard Meier, Steven Holl, Peter Eisenman, Greg Lynn, Charles Gwathmey, Daniel Libeskind, Ben van Berkel and Shigeru Ban.
Critics say six weeks is not enough time for the LMDC to make a choice that will mould the skyline of the city for generations to come and become a new symbol of the city and its regeneration.
Not since 1947, when an international design team convened to settle on a design for the United Nations headquarters, has the city had the opportunity to re-define itself so profoundly.
"New York has given itself a priceless gift," Herbert Muschamp, the architecture critic of the New York Times, wrote this week.
"It has opened the minds of Government officials to the idea of contemporary architecture.
"Thanks entirely to public pressure, our great city has taken a giant step towards reclaiming a place of world leadership in the civil art of building."
What will happen over the next six weeks will be, as Foster put it, an "incredibly, immensely important" debate over which plan best meets the demand for civic inspiration and the practical demands for the right combination of public and commercial space.
The final choice must also pay tribute to the dead of September 11, and families of the victims will have one of the most important voices in the selection process.
For example, while they may like Foster's park spaces and his two sunken voids with walls rising into the park, they may balk at his "twinned tower" design that resembles the old Twin Towers.
Libeskind - the German visionary behind the Jewish Museum in Berlin - proposes keeping the retaining walls of the foundations of the old World Trade Centre exposed to public view. Beside a tall tower, a second needle filled with gardens would rise even higher as "a constant affirmation of life".
Meier says the competition is the "most meaningful architectural project in this city's history".
His main structure looks almost like a noughts-and-crosses grid with gardens on the roofs of the crossing sections.
A park of trees, with subterranean running water and 2800 candles or lights, would extend to the edge of the Hudson River and on to a floating public park with room for 5000 people.
In his plan, the sites of the old towers would be reflecting pools of water on top of glass.
One message seems to emerge from the nine plans put forward: despite the nervousness lingering from the shock of the destruction of the Twin Towers, New York is not about to give up its love affair with the skyscraper.
But in choosing a final blueprint, the city must ask itself many questions.
Does it want to reclaim the honour of having the world's tallest building?
Should it embrace architecture that is stunning and utterly modernistic or is it better to take a more mellow approach and emphasise ground-level gardens and buildings more fitting with its urban history?
And, lastly, which of these plans is the most practical in financial terms.