Two years after the attack on the World Trade Center, intense passions still swirl around the redevelopment project.
This week, a group of victims' families gathered at the construction site in Lower Manhattan to protest against plans to rebuild on the foundations of the obliterated twin towers.
They argue it constitutes a sacred cemetery for the thousands of people who died there.
This latest protest is one of countless wrangles that have dogged the project so far. The rebuilding has only inched forward and looks certain to take a lot longer to complete that first planned.
Further, designs to rebuild the 17-acre complex may yet be altered by the powerful parties who hold a stake in the site.
Last February, architect Daniel Libeskind won a competition to redesign the World Trade Center site, in a very public selection process.
With its overt symbolism, the design was a popular choice. But, since then, Mr Libeskind's artistic vision has clashed with the commercial demands of prime real estate.
Many people, such as the victims relatives' groups, are questioning whether the public's voice will, in the end, be drowned out.
Wedge of Light: A triangular piazza whose shape is defined by the angles of the sun between 0846, when the first plane hit the first tower, and 1028, when the second tower collapsed. It is designed to ensure no shadow falls on the site between those times
Heroes Walk: Will trace the firefighters' paths as they raced into the trade center
Part of the problem is that this is widely seen as one of the most important urban redevelopment sites in the world and there are so many interested parties whose differences need to reconciled - victims' families, downtown residents, businessmen, architects, developers and politicians.
Responsibility for the site is divided between the governors of the states of New York and New Jersey, who own the land through the Port Authority and Larry A Silverstein, the leaseholder who holds the right to redevelop the office space.
Two main features of the Libeskind plan aroused opposition from the outset - the centrepiece "Freedom Tower" and a sunken memorial garden, which was welcomed by victims' relatives.
The tower was to be 1,776ft (540m) high, echoing the date of the founding of the republic. Its off-centre spire at the top conjured up the Statue of Liberty's torch.
Changing the spiral
But business groups and leaseholder Mr Silverstein questioned the wisdom of building such a large tower. They asked whether companies would, indeed, want to lease space in such a tall building anymore.
Although Mr Silverstein has no legal right to say what should or should not be built, he has much financial and political clout. He is still paying the rent on the site and it is his multi-billion-dollar insurance claim that is paying for the rebuilding.
A property developer in his 70s, Mr Silverstein has already brought his weight to bear on the design of "Freedom Tower".
Relatives object to plans to build on the foundations of the towers
He argued that the symbolic spiral at the tip of the tower is too expensive to build and pushed for something more straightforward. As part of a compromise, Mr Libeskind relinquished control for the tower to another architect chosen by Mr Silverstein.
The property developer has also suggested that the tower be moved to a site closer to the transport hub, where he says it will be easier and more profitable to rent.
A further bone of contention in Mr Libeskind's plans is the 4.7-acre pit that was once the foundations, or footprint, of the twin towers. A 70-foot steel-enforced concrete "slurry wall", once encased these foundations.
After the attacks, the wall, which was all that was left of the trade center complex, kept the waters of the Hudson River at bay. Mr Libeskind has imbued it with heroic status, as an emblem to resistance to terrorism.
But Mr Silverstein and business groups argued that it would inflict a perpetually open wound on Lower Manhattan. They said companies moving into the trade center may not want to be constantly reminded of their vulnerability. Mr Silverstein also complained that the slurry wall, which was to remain exposed, was simply ugly.
Libeskind has imbued the wall around the original foundations with heroic status
Mr Libeskind originally intended the garden to go the full 70-feet down to the bedrock. This was welcomed by victims' families, who point out that many of their loved ones' remains are still there.
But in the spirit of commercialism there are now plans to build a subterranean shopping complex and a huge public transit terminal from 30ft below ground level.
Many downtown residents were against having the garden sunk at all. One survey carried out during the summer suggested that a majority of New Yorkers wanted it to be at ground level so it is easier to cross the site and reach the planned transportation hub, shops and office buildings.
Many of the victims' families fear that amid the talk of office space, building design, street grids, transit hubs and financing, their voices are becoming fainter.
Dan Cruickshank is a British architectural historian who has talked to relatives, politicians, planners, the leaseholder and the architects over a period of 14 months for a BBC programme documenting the evolution of the plans.
He concludes that while sentiment remained strong for a long time after the attacks, "it is all very ruthless again."
"New York is a very tough place," he says. "At first there were grand gestures to console the public but now it boils down to Larry Silverstein and his obligation to build office and commercial space.
"Mr Silverstein is hard-nosed and tough and he's the one calling the shots. Many of the victims' families are finding the whole process depressing. There was a sense of listening for a year but now commerce is coming to the fore."
Mr Cruickshank says the complex will be built over 20 years, as and when there is commercial demand. The real battle for how it will eventually look may only have just begun.
Towering Ambitions: Dan Cruickshank at Ground Zero is broadcast on BBC Two on Sunday 7 September at 2100 BST.