Like the cracked Liberty Bell enshrined here, it’s the irregularities and imperfections that add to Philadelphia’s rich texture and throw its polished aspects into relief. “Philly” is a palimpsest, its eras of history, culture and architecture layered upon (without obscuring) one another — from the quaint colonial streets of Old City to the steel-and-glass skyscrapers downtown. In between are stately Victorian estates, world-class art museums and universities, and a magnificent, sprawling green space, Fairmount Park, 10 times the size of New York City’s Central Park. Art lovers come to Philadelphia specifically to visit the idiosyncratic Barnes Foundation, which contains an astonishing collection of Impressionist and Old Master paintings. And the recently refurbished Rodin Museum is just across the street.