A change to the design of a needle that will sit atop One World Trade Center is raising questions over whether the building will still be America's tallest when completed.
The 408-foot-tall needle will no longer be enclosed in a fiberglass-and-steel enclosure called a radome, a feature that was recently removed from the original design because the building's developer says it would be impossible to properly maintain or repair it.
Without the enclosure, it's unclear whether the needle is an antenna or a spire -- a crucial distinction in terms of measuring the building's height. Without the spire, One World Trade Center would actually be shorter than the Willis Tower in Chicago, which currently wears the crown of tallest building in the United States at 1,451 feet, not including its own antennas.
Last week, the skyscraper became New York City's tallest building as workers erected steel columns that were just high enough to rise above the Empire State Building's observation deck. The building is being constructed to replace the twin towers destroyed in the Sept. 11, 2001, terror attacks.
Designs call for the tower's roof to stand at 1,368 feet -- the same height as the north tower of the original World Trade Center. With the needle, the building's total height will be a symbolic 1,776 feet, referring to America's founding in 1776.