Sears Tower, in Chicago, Ill., tallest building (1,454 ft/443 m) in the world. It is over 100 ft (30 m) taller than the World Trade Center in New York City. Designed by Skidmore, Owings and Merrill, the office building was erected in the mid-1970s as the headquarters of Sears, Roebuck and Company. Prefabricated welded steel frames form a vertical core for the 110 stories.
See also: Skyscraper.