One Liberty Place - ended Philadelphia's height informal limit

One Liberty Place, completed in 1987, was the first building in Philadelphia to exceed the height of the William Penn statue atop City Hall, ending an informal agreement that no downtown building would be taller than City Hall. Its construction altered the city's skyline and marked the beginning of a new era of high-rise development in Center City. The tower became, at the time, Philadelphia's tallest building and a visible symbol of late-20th-century growth.