The Willis Tower is a known Chicago skyscraper and landmark that was recently given a new moniker. People may recognize it by its former name, the Sears Tower. It is an old skyscraper, having been competed in 1973. It is considered as the tallest building in the United States.
The Willis Tower is a 108 story skyscraper standing 1,450 feet or 442 meters tall. It once held the distinction as the tallest building in the world during its completion in 1973. It is currently the fifth tallest free-standing structure in the world.
The Willis Tower was planned and conceived in 1969 when the then largest retailer in the world, Sears, Roebuck and Co. decided to put up a center where all its employees in the surrounding Chicago area will be able to consolidate in just a single office building. The company forecasted its continued growth that would require further office space aside from the immediate need of space reaching around 3 million square feet.
For the job, Sears commissioned Skidmore, Owings and Merrill to design a building that would become the largest office building in the world. The design team of architect Bruce Graham and structural engineer Fazlur Khan designed a structure composed of nine separate square tubes clustered in a 3×3 matrix. The first steel structure was first erected in 1971 and the building completed in May of 1973. Construction costs of the building totaled about $150 million, already quite a sum during those days.
The Tower Skydeck on the building was opened on June 22, 1974 as a public observation deck. Located on the 103 floor 1,353 feet or 412 meters above ground, it has become one of the most popular tourist attractions in the Chicago area. The deck provides a stunning view of the city that stretches as far as Michigan and Wisconsin on a clear day. There is also a second Skydeck located on the 99th floor of the building used when the main observation deck is closed.