In 1748, Giambattista Nolli engraved a beautiful plan of Rome, a map that has become, perhaps, the most influential drawing in the history of urbanism. Nolli drew the streets and the houses but then he added in the plans of the city’s many churches and public buildings, indicating the interiors of these as if they were piazzas.

Thus the language of within and without began to meld into one. The city was conceived not just as a network of streets and squares with solid shaded buildings but a more nuanced lacework of naves and apses, of porticos, lobbies and ruins in which the architecture rather than the streets becomes the city.