Workers will put up steel columns that will make the unfinished skeleton a little over 1,250 feet high. That's just enough to peek over the roof of the observation deck on the Empire State Building, but not as high as the Empire State Building's antenna.
Experts usually don't count antennas or flagpoles when measuring building height.
Workers are still adding floors to One World Trade Center. When complete, it will be the nation's tallest building at 1,776 feet -- if you count the 408-foot-tall antenna spire, called the Freedom Tower, that will sit on the roof.
If you don't count the Freedom Tower, Chicago's Willis Tower will stay on top of the list.
One World Trade Center isn't expected to reach its full height for at least another year.
Tallest Buildings in America:
The tallest completed buildings in the United States, as measured from the lowest public entrance to the highest architectural element, not including antennas. After it is finished, One World Trade Center may take over the top spot, but only if you count its rooftop spire, which reaches to 1,776 feet.
1. Willis Tower (formerly Sears Tower), Chicago, 1974: 1,451 feet.
2. Trump International Hotel and Tower, Chicago, 2009: 1,389 feet.
3. Empire State Building, New York, 1931: 1,250 feet.
4. Bank of America Tower, New York, 2009: 1,200 feet.
5. Aon Center, Chicago, 1973: 1,136 feet.
Source: Council on Tall Buildings and Urban Habitats.
The Associated Press contributed to this report. All rights reserved.