Modern infrastructure that invisibly delivers clean water and reliable power is often held up as a norm. Yet, in reality, it often fails, or even fails to exist, depending on where it is located and who it is intended to serve. In the face of accelerating climate change and inequality, disruptions to modern infrastructural systems are becoming more and more frequent. This suggests the need for a paradigm shift in how built environment fields envision, plan and design for sustainable settlements and the infrastructure systems which are integral to them. This course will begin with a critical historical grounding in sustainability, interrogating what previous framings have achieved and how sustainability interfaces with the current emphasis on resilience. We will then tap into current infrastructural theory, gleaning useful concepts for thinking through infrastructural interdependencies, disparities, cascading failures and exchanges between the Global North and South. We will bring these concepts to contemporary cases of failures, from power outages to water system disruptions, examining the extent to which these are a result of policy, technical, or physical limitations and the role of underlying structural processes such as racism and colonialism. Building on this foundation in what is not working, we will turn to emerging solutions, drawing from theory and case studies. We will engage with current discussions of passive survivability, safe-to-fail systems, and decentralization to envision alternative approaches to sustainability and the infrastructural systems that help shape it. In the final project, students will propose a pathway for scaling up an emerging alternative in an infrastructural domain and location of choice. Major assignments will be individual, however we will engage in a collaborative process to develop the tools to think through alternatives and to ultimately glean cross-cutting tactics and themes to take into future work.