Below the streets of the modern city lie the bowels of urban systemsUrban systems: sewers and other elements of infrastructureInfrastructure. These structures are often magnificent, to use the word of Giovanni Battista Piranesi: grand in size and impressive. Nevertheless, we avoid encounters with them, seeing them as filthy, odorous, even abhorrent. These shared yet largely hidden spaces owe their existence to collective action. The resolve and the wherewithal to undertake action on this scaleScale came about only after centuries of debate in the fields of architectureArchitecture, engineering, medicine, and law, among others. Once built, the spaces persist only through continued maintenance and public investment in the context of ongoing conflicts regarding the roles of individuals and groups. This chapter explores how the urban infrastructureUrban infrastructure beneath modern streets reflects notions of the wellbeing of the human body. It recounts how the city itself came to be seen as a body, with necessary functions performed by entrails kept out of view. In exploring the politics behind historic debates about streets, it lays the groundwork for continuing considerationsScale considerations of the role and structure of the street.