Sears, Roebuck and Co. began construction of the world's tallest skyscraper, the Sears Tower, in 1970 and celebrated its "topping-out" on May 3, 1973.

It appears that major flooding last Sunday caused a building-wide power outage at Chicago's iconic 1,450 ft.-tall Willis Tower (aka Sears Tower), which has since loomed ominously over the city's ...

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 ...

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 ...

A stunning photo captures lightning striking Chicago's Willis Tower, showcasing nature's power. Business Insider Subscribe Newsletters ...

The cracked coating of one of the glass bay of The Ledge, a popular tourist attraction on the 103rd story of the Willis Tower in Chicago. AP For the visitors present inside the balcony, it was a ...

Peter Tsai's passion project takes him high above the Windy City, to capture images of our spectacular skyscrapers shrouded in fog! He calls his photo series, 'Cloud Chicago'!

The Willis Tower has long been an attraction to tourists hoping to smash their foreheads against the Skydeck glass windows to get an aerial view of downtown Chicago's Loop.