Authorities are stepping up their investigation into the mail bombs addressed to Chicago synagogues, and they weren't the only Chicago locations showing up on al-Qaeda's radar.

The famed “Sears Tower” suffered a blackout Sunday after massive flooding caused a power outage in the famed high-rise.

The site of Sears Tower is cleared as construction begins. 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 ...

CHICAGO (CBS) --The Willis Tower is starting to show its age and is in need of a nip and tuck, so to speak. Around 160,000 people walk by the facelift in progress everyday. CBS 2 took a look ...

Willis Tower is visible through the most iconic element of the new 606 trail — a rebuilt bridge over Milwaukee Avenue, painted dark red like the historic bridges over the Chicago River.

Those who take an elevator ride up to the 103rd floor of Chicago's iconic Willis Tower will now find a newly renovated Skydeck Chicago viewing point and museum experience. The main attraction is ...

As the Willis (or do you still say "Sears"?) Tower turns 40, a new photo exhibit examines the building's visual impact on the city's landscape.

Willis told the name Sears to scoot on over, well now it’s their turn. United Airlines and its operations will be invading the building.

FILE – A Nov. 7, 2013 file photo shows a view of Chicago’s 110 story, 1,450 foot Willis Tower. Blackstone announced Monday, March 16, 2015 that it is buying Chicago s Willis Tower, once called the ...

Read Fast Facts from CNN about Willis Tower, formerly the Sears Tower, located in Chicago.

The Ledge tourist attraction at the Willis Tower has been closed after a report of cracking glass at the 103rd-floor attraction.

The site of Sears Tower is cleared as construction begins. 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 ...