This week, we’re taking a break from live recording. Guest host Marie-Claire Shanahan spends the hour looking at the infrastructure that makes our modern, increasingly urbanized lives possible. She’s joined by journalist Scott Huler, author of the book On the Grid: A Plot of Land, an Average Neighborhood, and the Systems that Make our World Work. And she’ll speak to environmental journalist and urban design critic Tim De Chant, about his population density blog Per Square Mile.