Rising from the ashes of 9/11, the new World Trade Centre tower has punched above the New York skyline to reach its powerfully symbolic height of 1,776ft and become America's tallest building. Or has it?
A committee of architects recognised as the arbiters on world building heights has been meeting to decide whether a design change affecting the skyscraper's 408ft needle disqualifies it from being counted. If so, it would deny the tower the title as the nation's tallest.
But there is more than bragging rights at stake - 1 World Trade Centre stands as a monument to those killed in the 2001 terrorist attacks and the ruling could dim the echo of America's founding year in the structure's height.
Without the needle, the building measures 1,368ft, a number that also holds symbolic weight as the height of the original World Trade Centre.
And the decision is being made by an organisation based in Chicago, whose cultural and architectural history is embodied by the Willis - formerly Sears - Tower that would be knocked into second place by a vote in favour of the New York structure.
"Most of the time these decisions are not so controversial," said Daniel Safarik, an architect and spokesman for the non-profit Council on Tall Buildings and Urban Habitat. The 30 members of its Height Committee are meeting to render judgment behind closed doors in Chicago, where the world's first skyscraper appeared in 1884.
The committee, comprising industry professionals from all over the world, will announce its decision next week.
The question over 1 World Trade Centre, which remains under construction and is expected to open next year, arose because of a change to the design of its tower-topping needle. Under the council's current criteria, spires that are an integral part of a building's aesthetic design count; broadcast antennas that can be added and removed do not.
The designers of 1 World Trade Centre had intended to enclose the mast's communications gear in decorative cladding made of fibre glass and steel. But the developer removed that exterior shell from the design, saying it would be impossible to properly maintain or repair.
Without it, the question is whether the mast is now primarily just a broadcast antenna.
According to the architecture firm behind the building, Skidmore, Owings & Merrill, the needle will have a communications platform for radio and television equipment, but it will also be topped with an LED beacon that will fire out a horizontal blaze of light visible from up to 50 miles on a clear night - a feature that has been described as a crowning beacon of hope.
The developers tested the lights last night and hundreds of red, white and blue LED modules illuminated lower Manhattan.
Mr Safarik said the committee could consider amending its height criteria - a move with much broader implications that could force a reshuffle in the rankings of the tallest buildings in the world.
If the matter were not so steeped in emotion it might have set off some of the good-natured ribbing emblematic of the history of one-upmanship between New York and Chicago. But 1 World Trade Centre is a monument to American resilience admired well beyond Manhattan.
"I don't think anybody's going to argue with the pride in building that new tower," said 31-year-old software developer Brett Tooley, who works opposite the Willis Tower. "Not only is it going to be the tallest building; it's going to be one of the strongest buildings in the history of America. It's a marvel of engineering."
"We take our hats off to them out here in Chicago and the Midwest," said Robert Wislow, chairman and chief executive of US Equities, the firm that manages the Willis Tower. "And we welcome the building to the elite club of the tallest buildings in the world. Nobody's looking at this like a competition."
Still, the Willis has a central place in Chicago's history, speaking to the city's own tradition of recovering from adversity ever since the 1871 Great Fire and its history of creating architectural marvels, said Peter Alter, an archivist at the Chicago History Museum.
Skidmore, Owings & Merrill, based in Chicago, also designed the Willis. Then known as the Sears Tower, it was completed in 1973 and remained the tallest building in the world until 1996 when the council ruled that the Petronas Twin Towers in Kuala Lumpur, Malaysia, had knocked it from the top spot.
The Burj Khalifa in Dubai is currently world's tallest building, standing 2,722ft.
And the Willis can still claim to get visitors up higher: The highest occupied floor in the 1,450ft (not including antenna height), 110-storey Willis Tower is still higher up than that of the 104-storey 1 World Trade Centre. In a sign of just how in dispute building measurements can be, the council says the Willis has 108 floors.
At the Willis' 103rd floor, thrill-seekers can step out into one of the glass boxes known as The Ledge that extend outside the building's steel frame and look straight down 1,353 feet.