Friday's finalinstallation, 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.
Installation of the final two sections of the 408-foot, 758-ton spire was completed after pieces of it had been transported to the roof of the building last week.