A critical and interdisciplinary exploration of our world’s continuously urbanizing and expanding coastline. For centuries, cities have grown and expanded onto previously saturated grounds; “reclaiming” land from estuaries, marshes, mangroves, and seabeds. While these artificial coastlines are sites of tremendous real estate, civic, and infrastructural investments, they are also the most vulnerable to the effects of climate change. Terra-Sorta-Firma documents the global extent of reclaimed coastal lands, and provides a framework for comparison across varying geographies, cultures, and histories. It renders visible the ubiquity and precarity of urban coastal reclamation in an age of increased environmental and economic indeterminacy. It challenges designers, developers, policymakers, engineers, and urbanists to reconsider the design and construction of land itself, and to re-imagine this most fundamental of all infrastructures along a gradient of inundation.