One World Trade Centre in New York has become America's tallest building and the world's third tallest building after topping out at a height of 541 metres.
A 124-metre steel spire was installed last Friday, pushing the skyscraper's height to 1776 feet, commemorating America’s independence in 1776.
The tower was built at a cost of $3.9 billion, giving it the title of most expensive office building in the world
Previously known as the Freedom Tower, the building is located in the northwest corner of the site where the former World Trade Center towers were destroyed in the 11 September 2001 attacks.
The tower was originally designed by Daniel Libeskind, the architect behind the master plan for the entire Ground Zero site, however after it underwent numerous revisions, US firm Skidmore, Owings & Merrill LLP was brought in to oversee its design.
[caption id="attachment_2668" align="aligncenter" width="361"] Source: Wikipedia.com[/caption]
Debate has been circulating as to whether the tower’s spire is actually a removable antenna - a vital distinction in measuring building height.
The Council on Tall Buildings and Urban Habitat, a Chicago-based organization considered an authority on such records, says an antenna is something simply added to the top of a tower that can be removed. By contrast, a spire is something that is part of the building's architectural design.
Without the spire, One World Trade Centre would be shorter than the Willis Tower in Chigao, which stands at 1,451 feet and has, until now, the title of tallest building in the US, not including its antennas.
The world’s tallest building, Burj Khalifa in Dubai, stands at around 2,722 feet.
The Twin Towers were about 1,360 feet tall, not including the antenna on one of them.
The spire at One World Trade Center will serve as a television and radio antenna, and it will feature an LED-powered light that will be visible from tens of miles away, said Scott Rechler, the vice chairman of the Port Authority of New York and New Jersey, which owns the lower Manhattan trade center site. The light, which will change colors, is to be activated in the next few months.
When finally completed it will offer 241,000 square metres of commercial office space as well as observation decks, TV broadcasting facilities and restaurants.
One World Trade Centre has been developed by the Port Authority of New York and New Jersey who retain ownership of the tower.
Larry Silverstein of Silverstein Properties is the leaseholder and developer of the complex, controlling the balance of the site under a 99-year lease agreement.
Other key players include private real estate company Durst Organisation who purchased a 5% equity stake in the tower for a $100m investment.
Durst are responsible for supervising the building's construction, and managing the tower on behalf of the Port Authority, having responsibility for leasing, property management and tenant installations.
By September 2012, around 55 percent of the building's floor space had been leased, with key tenants including magazine publisher Conde Nast,
the government's General Services Administration
and Vantone Holdings China Center, which will provide business space for international companies.
The tower has been constructed by local contracting firm Tishman Realty & Construction.
Another building on the site, Four World Trade Centre, was completed last year, while Ground Zero features two fountains sunk into the site of the former Twin Towers.