The Renaissance Superstructure charts the sixteenth-century reinvention of what Morgan Ng calls the superstructure: a typology of elevated defensive corridors that emerged during the Middle Ages and once traversed many European cities. Not unlike private helicopters today, such pathways afforded rulers secure and privileged mobility, enabling them to travel between their urban and extramural strongholds while remaining high above the chaos of the street. Against all odds, superstructures continued to thrive well into the early modern period, despite their military vulnerability in the age of artillery warfare. By morphing from utilitarian defenses into monumental systems of circulation, they served the rising bureaucratic, ritual, and symbolic demands of absolutist courts. The unlikely survival of an obsolescent architecture opens a window onto the complex dynamics of technical evolution and cultural change.