One World Trade Center another step closer to completion NEW YORK One World Trade Center is another step closer to completion and becoming the tallest building in the Western Hemisphere. CBS New York reports the final two sections of the 408-foot spire that will sit on top of the building were raised up to the roof onto a temporary platform Thursday morning. They will be installed at a later date. Once the spire is fully installed, the building will stand at 1,776 feet Construction workers applauded as a crane hoisted the U.S.-flag-covered spire to the top of One World Trade Center. "It's a prideful day," one worker said. It's a great day to be an American. The raising of the pieces was originally scheduled for Monday but was postponed because of bad weather. The spire pieces were shipped from Canada and New Jersey. One World Trade Center: A view from the top The spire will serve as a world-class broadcast antenna and provide public transmission services for television and radio broadcast channels that were destroyed on Sept. 11, 2001, along with the trade center towers. The building is already the tallest in New York City and, once completed, will become the tallest building in the Western Hemisphere and the third tallest in the world. One World Trade Center is set to open in 2014.