Philadelphia was built as a grid in the 17th century, with five public squares, four of which are now parks, the fifth is city hall, in the center of the city.

Philadelphia was built as a grid in the 17th century, with five public squares, four of which are now parks, the fifth is city hall, in the center of the city. It's old enough to have respectable (for an American city) transit infrastructure - electric trains, subways, trolleys, buses, an active ferry to Camden, and more. Fairmount park is one of the largest urban parks in the world, although getting a straight answer about acreage can be a little tricky.