NEW YORK -
The silver spire topping One World Trade Center has been fully installed on the building's roof.
That brings the iconic structure to its full, symbolic height of 1,776 feet.
The Port Authority of New York and New Jersey says the spire's installation was completed Friday morning.
Pieces of the spire were transported to the roof of the building last week.
It weighs 758 tons.
The 408-foot spire will serve as a world-class broadcast antenna.
An LED-powered light emanating from it will be seen from miles away.
The new tower is at the northwest corner of the World Trade Center site, which is well on its way to reconstruction with the 72-story Four World Trade Center and other buildings.
If it didn't have the spire, One World Trade Center would actually be shorter than the Willis Tower in Chicago, which stands at 1,451 feet and currently has the title of tallest building in the U.S., not including its own antennas.
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.