Design flaws in first iteration of the John Hancock Tower's cladding of mirrored glass panels caused segments to crack and fall out when the building flexed under the wind. Photo courtesy of the U.S. National Archives

What: John Hancock Tower repairs
When: Oct. 1, 1973
Where: 200 Clarendon St., Boston 

Architect I.M. Pei & Partners announces that more than 10,000 window panes will be replaced at the John Hancock Tower in Back Bay, after hundreds of panels plummeted to the ground during construction of New England’s tallest skyscraper. 

Plywood panels had dotted portions of the 60-story tower’s distinctive mirror facade while Massachusetts Institute of Technology researchers studied the cause of the problem. They identified flaws in the design of the double-paned windows, which were replaced with single-sheet panes. 

The property was renamed 200 Clarendon St. in 2015 by its current owner, Boston Properties. 

“Indigo cloud-shreds dot a band of tan;
the Hancock Tower bares a slice of night.”
— John Updike, “The City Outside” 

To celebrate its 150th anniversary, Banker & Tradesman is highlighting significant moments in the history of Massachusetts’ real estate and banking industries. To suggest a topic, email

This Month in History: The End of the ‘Plywood Palace’

by Steve Adams time to read: 1 min