At the heart of downtown Philadelphia is City Hall, a wedding cake of a building that would look more at home in Paris. It is the nation’s largest municipal building—even larger than the U.S. Capitol—and tallest masonry building (it is made of granite, brick and marble). Its soaring clock tower supports a 27-ton, 37-foot statue of William Penn. Just below the statue is a public observation deck, roughly 40 stories above ground, offering visitors a panoramic view of the city. There are 700 rooms in City Hall. Don’t miss the rich décor of the interior gallery, Conversation Hall and Mayor’s Reception Room—think gilded and coffered ceilings, ornately carved wood paneling and embossed ceramic tiles. The eight-sided staircase is another must-see and the dome crowned with cherubs in the Caucus Room. It’s a wonder that City Hall was ever threatened with demolition—its elaborate architecture has been criticized over the decades as too decadent for the city’s Quaker heritage. Rest assured though, that the future of this masterpiece remains secure.