#2: John Hancock Tower – Boston (1973)
Boston’s John Hancock Tower, now officially 200 Clarendon Street, became famous for a problem that was impossible for pedestrians to ignore: its enormous reflective windows began falling out. Soon after construction, large panes unexpectedly cracked and detached from the façade, occasionally crashing onto surrounding streets and forcing authorities to close areas below during dangerous conditions. At one point, so many missing windows were temporarily replaced with plywood that locals mockingly referred to the skyscraper as the “Plywood Palace.” Investigators eventually traced the failures to the behavior of the tower’s innovative insulating glass units, which were unable to tolerate the stresses imposed on them as expected. The solution required replacing roughly 10,000 windows, essentially rebuilding the glass skin of the 60-story structure at enormous expense. The tower also experienced excessive swaying that required additional engineering measures, including a tuned mass damper.
