Bart Sullivan, a senior vice president at WSP Cantor Seinuk, a firm that handles engineering for buildings like One World Trade Center, says building a residential skyscraper is generally more challenging than building a tall office building, partly because residential buildings have fewer internal columns and other core structural elements.

WSJ: Living The High Life

Under construction since 2006, One World Trade Center surpassed the Empire State Building (1, 250 feet) as the city's tallest structure in April.

CNN: Obama signs beam of One World Trade Center

Friday's final installation, raising the building's height to 1, 776 feet, makes One World Trade Center the tallest skyscraper in the U.S. and 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.

WSJ: Spire permanently installed on WTC tower

The addition of the spire, and its raising of the building's height to 1, 776 feet, makes One World Trade Center the tallest structure in the U.S. and 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.

WSJ: Spire permanently installed on WTC tower

New York (CNN) -- Construction crews at the 16-acre World Trade Center site will raise the final two sections of a 408-foot spire to the top of One World Trade Center on Monday morning, making the building the tallest in the Western Hemisphere, according to the site's management.

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While under construction, One World Trade Center became New York City's tallest building a year ago, standing 1, 271 feet above street-level.

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And here in the US, we were excited to peep some beautiful new renderings of One World Trade Center, showing New York City's tallest new building from a number of different vantage points.

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The visit will be a preview of the One World Trade Center topping-off ceremony, which will symbolize the near-completion of the iconic building's framework.

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