I take slight issue with this quotation -

> Though the idea of a street grid seems perfectly ordinary to city-dwellers today, it was unusual at the time. Most great cities in Mesopotamia, for example, had curving streets and a more organic-looking layout.

Maybe a street grid seems ordinary if you live in a large city in the US, but most European cities don't have gridded streets (and I don't think it's the norm in many other places in the world either).