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)
Doug Stanglin, USA TODAY
It's official: 1 World Trade Center Tower in Manhattan is the nation's tallest building.
Chicago's Willis Towers threatened to take the top spot after a design change for the needle on top of the trade center building raised the question of whether it was part of the structure or an add-on, like an antenna
The ruling by the Height Committee of the Council on Tall Buildings and Urban Habitat, which is the final arbiter of building heights around the world, means the building can claim its full 1,776-foot height.
The 1,776 figure is symbolically important for the tower that was built on the site of the Sept. 11 attacks.
Without the needle's extension, the building would have stood only 1,368 feet tall, well below the 1,450-foot Willis Tower, formerly known as the Sears Tower.
The decision was announced at simultaneous news conferences in Chicago and New York City.
The designers of 1 World Trade Center, which is set to open in January, had intended to enclose the mast's communications gear in decorative cladding made of fiberglass and steel. But the developer removed that exterior shell from the design, saying it would be impossible to properly maintain or repair.
The official designation now leapfrogs the building into the third spot for tallest building in the world, surpassing the 1,667-foot Taipei 101 in Taiwan.
But no building offers any imminent threat to Burj Khalifa, the 163-floor office, hotel and residential building in Dubai that towers over all the rest in the world at 2,717 feet.