The John Hancock Center was the tallest building outside Manhattan by the time its construction was completed .
422 , American Architecture : A History , Leland M. Roth , Westview Press , 2003 , ISBN 0-8133-3662-7 When the building topped out on May 6 , 1968 , it was the second tallest building in the world and the tallest outside of New York City .
John Hancock Center