It's official: New York City's new World Trade Center will be the tallest building in the United States once it's completed and open for business.

The Height Committee of the Council on Tall Buildings and Urban Habitat, an expert committee of architects that serves as the final word on such things, announced the big news at a press conference this morning in Chicago. The declaration means that the Windy City's Willis Tower (formerly and still commonly known as the Sears Tower) will fall to no. 2 on the U.S. list once World Trade Center opens its doors sometime next year.

A final ruling was needed to settle the debate over whether WTC's 408-foot needle would count toward its official height. With it, the tower measures 1,776 feet tall; without it, it would have been only 1,368 feet tall, or 83 feet shorter than the 1,451-foot Willis Tower. Ultimately, the panel decided that the needle will count because it serves as a spire not an antenna. "The key word is permanence," Antony Wood, the panel's executive director, said in explaining the decision, adding that the symbolic height of the building-spire combo helped convince the panel that the building's height will remain the same for the foreseeable future.