Vitruvius describes the architect’s responsibility for building private structures as only a secondary pursuit—their primary function is the design of “works for general use in public places,” best translated into contemporary parlance as “infrastructure.” This seminar assumes the simple counterfactual that architects, as they were during the time of Vitruvius, are again responsible for the design of all national, state, and local infrastructures. As an axiom the course assumes that the resources, estimated at $20 trillion through 2050, slated for the upkeep of the old infrastructure of the twentieth century, largely driven by the needs of cars and petroleum, instead be used to fund new ideas, designed by students, that may involve solar fields, algae farming, hydrogen cells, geothermal drilling, hyper-efficient batteries, industrial drones, and magnetic levitation or may involve systems that speculate even farther into the future of technological, and cultural, possibilities. For this ambitious project, Yale is collaborating with the Southern California Institute of Architecture (SCI-Arc) with two simultaneously taught courses: a seminar at Yale and a studio at SCI-Arc. Students work on a single project for the term, individually or in groups, and speculate on particular aspects of the future of American infrastructure in which they are interested. Each project is limited to a budget of $20 trillion US. Partially funded by the School, Yale students join the SCI-Arc students for a joint workshop in Los Angeles over a five-day period during Yale’s two-week spring break. Enrollment limited to ten.