The final section of the spire sits on top of One World Trade Center May 10, 2013 in New York after it was fully installed on the building's roof. (TIMOTHY A. CLARY/AFP/Getty Images)
To cheers from spectators and workers alike, construction crews set a silver spire atop New York City's One World Trade Center on Friday to bring the structure to its full 1,776 height and cap an emotional 12-year effort to restore a key part of the city skyline shattered by the 9/11 terror attacks.
The 408-foot spire, which weighs 758 tons, includes a broadcast antenna and a light that will be visible from miles away to serve as a both a beacon for aircraft and a permanent signal of triumph over extremists who jolted the city and the country.
"This really is a symbolic moment because this building really represents the resiliency of this country," Port Authority Vice Chair Scott Rechler told TODAY's Matt Lauer, who was perched on the 104th floor to witness the process. "These people, the thousand men and women who have worked here tirelessly, really as a tribute for the people that perished on 9/11 right on this site."
The needle will be held in place by a temporary structure until iron workers finish off the permanent base in the coming weeks.
The 1,776 feet - or 541 meters - is symbolic of the year 1776, when the U.S. declared its independence.
The building is rising at the northwest corner of the site where the twin towers were destroyed in the Sept. 11, 2001, terror attacks. The area is well on its way to reconstruction with the 72-story Four World Trade Center and other buildings.
The tower is scheduled to open for business in 2014. Tenants include the magazine publisher Conde Nast, the government's General Services Administration and Vantone Holdings China Center, which will provide business space for international companies.
The elegant spire gives the building the extra height needed to claim the status as the tallest structure in the U.S. and the third-tallest in the world, although building experts dispute whether the spire is actually an antenna - a crucial distinction in measuring the building's height.
Without the spire, One World Trade Center would be looking up at the Willis Tower in Chicago, which tops out at 1,451 feet, 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.