44K views · 841 reactions | Wind blowing off Lake Michigan is a common challenge to architects and engineers building in Chicago. Here's how Fazlur Kahn, structural engineer of Willis (Sears) Tower, developed a system capable of distributing the load of the building's 110 stories in the face of even the strongest gusts. | Chicago Architecture Center | Facebook

3.7K views · 85 reactions | For over 40 years, the name Sears invoked an image of a tall black tower in Chicago’s skyline. Although still commonly referred to as the Sears Tower, London-based insurance broker Willis Group Holdings, Ltd. obtained the naming rights to the building on July 16th 2009. Sears’ legacy as one of Chicago’s mail-order giants, however, goes back further than the construction of the Sears Tower in 1974. | Chicago Architecture Center | Facebook

Here's what it looks like 1,447 feet in the air standing on the west tower (or "superstructure") of The John Hancock Center. For most of its history, the two towers atop "Big John" were of equal height. When Channel 2 WBBM installed their new digital antenna in 2002, The east tower was rasied to overcome "ghosting" from the Willis Tower nearby. | theTV.website/