One Liberty Place - skyline landmark that broke the height 'gentlemen's agreement'

One Liberty Place, completed in 1987 at this Market Street address, was the first skyscraper to exceed the informal agreement that no building in Philadelphia should be taller than the statue of William Penn atop City Hall. The 61-story tower transformed the Center City skyline and triggered a wave of high-rise development in the late 20th century. It remains a prominent commercial and architectural landmark in the downtown business district.