Built well, a city should provide a bulwark against disaster. Fundamentally, all cities are fortresses. Or at least they should be. If a city is a fortress, where’s the wall? The edges of North American cities today aren’t edge-like at all. Most of them, especially in the West, ooze outward in a gradient, urban to suburban to exurban to rural to wild.

Get in-depth coverage of current and future trends in technology, and how they are shaping business, entertainment, communications, science, politics, and society.

Advertisement