
The Sears Tower is a skyscraper in Chicago, Illinois. It has been the tallest building in the United States since 1973, surpassing the World Trade Center, which itself had surpassed the Empire State Building only a year earlier.
Construction commenced in August 1970 and the building reached its originally anticipated maximum height on May 3, 1973. When completed, the Sears Tower had overtaken the roof of the World Trade Center in New York City as the world's tallest building. The tower has 108 stories as counted by standard methods, though the building owners count the main roof as 109 and the mechanical penthouse roof as 110. The distance to the roof is 1,451 feet (442 m), measured from the east entrance.[4]
On August 12, 2007, the Burj Dubai in Dubai, United Arab Emirates was reported by its developers to have surpassed the Sears Tower in all height categories.