One World Trade Center comes alive 13 years after 9/11

The One world Trade Centre that rose from the ruins of New York's iconic twin-tower World Trade Centre opened for business on Monday, with anchor tenant magazine publishing giant Conde Nast moving in with its 175 employees.

The new silvery skyscraper, New York's tallest building, resurrected from the ruins of the 11 September 2001 terror attacks, now stands tall as a symbol of American resilience.

The new tower, the centrepiece of a five-tower complex, stands 104 stories and 1,776 feet (540 meters) tall, a height representing the year the United States declared its independence from Britain.

The iconic Manhattan landmark had collapsed in fire and smoke on 11 September 2001, after being hit by hijacked airliners flown by Al-Qaeda militants, killing nearly 3,000 people. The al-Qaeda militants also targeted the Pentagon.

It took nearly 13 years to rebuild the tower, due mainly to political infighting. ''Some people are nervous, some people are just excited to move downtown and start a transformation for the company, to help revitalise lower Manhattan,'' said John Duffy, director of policies and controls at Conde Nast.

Condé Nast's 175 employees who moved into the new tower include Vanity Fair's Graydon Carter, Vogue's Anna Wintour and the New Yorker's David Remnick - occupying offices on floors 20 through 44 of the 104-floor ''Freedom Tower,'' officially 1 World Trade Center.

For the moment, the 1,776-foot skyscraper will not open access to its breathtaking 102nd-floor observation deck before it opens in the spring.

''Condé Nast is proud to be a part of this important moment of renewal for the city of New York,'' said Condé Nast spokeswoman Patti Rockenwagner.

''We are excited about contributing to the vitality of this community for years to come.''

Rockenwagner said Conde Nast's  3,400 staffers who are slated to move in will not relocate all at once. The company is planning to move in stages from its Times Square offices and plans to fill its new home by the end of February.

New Yorkers and tourists celebrated another milestone in the area's remarkable comeback.

''It's a beautiful thing,'' said a construction worker at the WTC site, where he toiled for 12 years on the landmark. ''People were depressed from before. Now, they are more happy that they see a positive change.''

New to the neighborhood is a battalion of added police officers. Nearly 50 Port Authority cops patrolled the area in the days before 9/11. That number has since doubled, with plans for up to 200 by the time all the signed tenants move in.

The tallest building in the Western Hemisphere, which cost $3.9 billion to build, was originally scheduled to open in 2006, but cost overruns and political infighting caused several delays.

Condé Nast was one of the first major tenants to sign a lease. Other tenants include the General Services Administration and the advertising firm Kids Creative.

Although the Port Authority, which owns the tower, has hailed the opening, only 60 per cent of the building has been leased, so far.