An aerial view of the topping out of the Sears Tower on May 3, 1973, in Chicago. Sears Tower, designed by Skidmore, Owings and Merrill, is the worlds tallest building on May 18, 1973, in Chicago.

The Sears Tower, right, begins to take shape in downtown Chicago in the early 1970s. Workers take in the view from the 80th floor of the Sears Tower under construction on November 6, 1972. The ...

Not content with having the tallest building in America, the owners of Sears Tower in Chicago have installed glass box viewing platforms which stick out of the building 103 floors up.

The Sears Tower, right, begins to take shape in downtown Chicago in the early 1970s. Workers take in the view from the 80th floor of the Sears Tower under construction on November 6, 1972. The ...

Sears announced plans to build a new downtown headquarters in Chicago in 1969. Four years later the Sears Tower opened. When it opened in 1973 the 110-story building became the tallest building in ...

At Chicago's Willis Tower, check out "Pie in the Sky," where you get a VIP dining experience on the 103rd floor of the tallest building in the Western Hemisphere. The food is fine, but the view ...

CHICAGO -- For Chicagoans it may be the architectural equivalent of having to watch Michael Jordan finish his career in a Washington Wizards uniform: The Sears Tower is turning into something ...

This summer, the Sears Tower plans to add four enclosed glass-bottomed balconies jutting out from the building's 103rd-floor Skydeck -- offering a view of 1,353 feet down.

From Atop Sears Tower, A Ledge With A View A new ledge opens at the Sears Tower Skydeck in Chicago. The enclosed glass box extends 4 feet from the building and allows visitors to stare 1,353 feet ...