Did You Know....? - Strange Structures

Ever since it was built in 1972, the 60-storey John Hancock Tower in Boston, Massachusetts, has suffered from windows suddenly popping out and shattering on to the street below. The John Hancock Mutual Life Insurance Agency tried to remedy the problem by replacing all 10,334 windows with 400lb sections of tempered glass, but still windows continued to smash for no apparent reason. So now the company hires 2 permanent guards who do nothing but patrol the street and look out for cracked panes before the come crashing down onto passers-by.