233 South Wacker Drive
The Sears Tower is the tallest building in the United States, by the measurement from the ground to its roof. Commissioned by Sears, Roebuck and Company, it was designed by chief architect Bruce Graham and structural engineers Srinivasa "Hal" Iyengar and Fazlur Khan of Skidmore, Owings & Merrill.
Construction commenced in August 1970 and the building reached its originally anticipated maximum height on May 3, 1973. 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. Or 101 stories if you don't count any of the mechanical floors. The distance to the roof is 442 m (1,450 ft 7 in), measured from the east entrance.
The Sears Tower Skydeck observation deck on the 103rd floor of the tower is 412 m (1,353 ft) above ground. Tourists can experience how the building sways on a windy day. They can see far over the plains of Illinois and across Lake Michigan to Indiana, Michigan and Wisconsin on a clear day. It only takes about 45 seconds to soar to the top in either of two special elevators.
* Content provided by the Chicago Sears Tower