On November 12, 2013, the Council on Tall Buildings and Urban Habitat (CTBUH) ruled that the official height of One World Trade Center in New York is 1776 feet (541 meters), based on the height to its architectural top. In doing so, the CTBUH confirmed that the 408-ft spire topping off the structure was a permanent architectural element and not just a broadcast antenna. "Today's decision is a milestone for defining what is considered to be a part of structure and design to be counted as the height measurement," said Wai-Fah Chen of the Department of Civil and Environmental Engineering of the University of Hawaii at Manoa.
When One World Trade Center is completed and occupied in 2014 it will be the tallest building in the United States, surpassing the Willis (formerly Sears) Tower in Chicago (1451 ft / 442 m), and the third tallest building in the world. See also: Architectural engineering; Buildings; Structural design; Structural design of high-rise towers; Structure (engineering)