Chicago's Willis -formerly Sears- Tower is losing its 'tallest building in the US' title. The Height Committee of the Council on Tall Buildings and Urban Habitat announced today (Tuesday) in Chicago, that One World Trade Center in New York City will be number one upon its completion next year. Antony Wood, Executive Director of the group, says the spire on One World Trade Center -- which makes it higher than Chicago's Willis Tower -- is not considered an antenna. "Antennae do not count in the height of a tall building," Wood said, "because they are functional technical equipment which is put on top. The committee were quite clear that that was not the case on One World Trade Center. This is a permanent feature." After 39 years of holding the title of America's Tallest Building, Sears, or Willis, will be number two in the U.S.