NEW YORK – One World Trade Center, the monolith being built to replace the twin towers destroyed in the Sept. 11, 2001, attacks, claimed the title of New York City’s tallest skyscraper Monday, as workers erected steel columns that made its unfinished skeleton a little over 1,250 feet high, just enough to peek over the roof of the observation deck on the Empire State Building.

City officials and iron workers applauded as the first 12-ton column was hoisted onto the tower’s top deck.

“This project is much more than steel and concrete. It is a symbol of success for the nation,” said David Samson, chairman of the Port Authority, the agency that owns the World Trade Center.

Clear skies afforded an immaculate 360-degree view from the top, although it wasn’t easy getting up there. After riding an elevator to the 90th floor, a small group of officials and journalists had to climb three steep ladders to reach the top platform, which was encircled by blue netting along the perimeter.

The milestone is a preliminary one. Workers are still adding floors to the building once called the Freedom Tower. It isn’t expected to reach its full height for at least another year, at which point it is likely to be declared the tallest building in the United States, and third-tallest in the world.

Those bragging rights, though, will carry an asterisk. In this case, the issue involves the 408-foot-tall needle that will sit on the tower’s roof.

Count it, and the World Trade Center is back on top. Otherwise, it will have to settle for No. 2, after the Willis Tower in Chicago.

“Height is complicated,” said Nathaniel Hollister, a spokesman for The Council on Tall Buildings and Urban Habitats, a Chicago-based organization considered an authority on such records.

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. The building’s roof will be topped with a 408-foot, cable-stayed mast, making the total height of the structure a symbolic 1,776 feet.

Without that spire, One World Trade Center would still be smaller than the Willis Tower in Chicago, formerly known as the Sears Tower, which tops out at 1,451 feet (not including its own antennas).