The 60-story John Hancock Tower in Boston, designed by Henry N. Cobb of I. M. Pei & Partners, was meant to read as a single sheer plane of blue glass. Its problems started in 1968 in the Back Bay mud, where temporary retaining walls warped under the pressure of wet clay, damaging utilities and the historic Trinity Church across the street, which won an $11 million settlement. Once the facade went up, its 10,344 panes, each 4 by 11 feet and 500 pounds, began falling to the sidewalks. Police closed the surrounding streets whenever winds reached 45 miles per hour, and the gaps were covered in plywood, earning nicknames like the Plywood Palace.

An independent lab traced the breakage to thermal stress in a rigid bond between the double panes, and every window was replaced with single-pane heat-treated glass at a cost of up to $7 million. Upper-floor workers then got seasick, so two 300-ton lead tuned mass dampers were installed on the 58th floor. Worse, tests on an aeroelastic model at MIT’s Wright Brothers Wind Tunnel showed the tower could tip over under certain winds on its narrow sides, and crews working at night added 1,500 tons of diagonal steel bracing to the core. The building opened in 1976, five years late, at roughly $175 million instead of $75 million, and still won AIA honors in 1977 and the 25 Year Award in 2011.

• The discount chain Building #19, which sold removed tower windows for $100 each and joked about the plywood
• How the lead dampers slide on lubricated plates and work in pairs to resist twisting
• Cobb’s missing spandrel panels, minimal mullions, and notched short sides that make the tower look like a sheet of glass
• A 2006 purchase at $1.3 billion, a 2009 foreclosure auction at $660 million, and a 2010 resale for $930 million
• The 2015 renaming to 200 Clarendon Street, the observation deck closed after 9/11, and the artist JR’s giant mural