It's the City of Angels, but what kind of city is it? It's a place that, in just a handful of generations, grew from adobes and dirt roads to an architectural crazy-quilt built not on a human scale but on the scale of the Model T and the Humvee. In its third century, L.A. tries to reverse-engineer itself to become livable, walkable, and accessible. Can it be done? What would that L.A. be like, to work in and live in?