Boston Hancock

The tallest building in Boston is the John Hancock Tower, designed by lead architect Henry N. Cobb of the firm Pei (Buddhist) Cobb (Boston Brahmin) Freed (Jew) & Partners.

During construction, the 60-story tower shed many of its 500-pound blue glass windowpanes. Because of the extreme hazard, streets were closed during high winds, and the uncompleted building had to be temporarily boarded up with plywood.

The failure was ultimately traced to the design of the dual-pane windows, which could not handle the stress from temperature changes and high-altitude winds. This required the builders to completely remove and replace all 10,344 windowpanes with single-pane tempered glass at a massive expense.

​In the years immediately following the reconstruction, window washers were tasked with visually inspecting every single pane of glass from the outside to spot microscopic fractures.

​It was a stroke of luck that no one was killed.