This thesis investigates a particular Terrain Vague as a spatial and phenomenological condition in New York City. Through a series of photographs and cast models, it seeks to demonstrate the importance of Terrain Vague in a global metropolis. For the purpose of this study, Terrain Vague is investigated through the lens of the largest and most valuable privately-owned vacant piece of land in Manhattan. Formerly home to Con Edison's Waterside Power Station, this empty property acts as the antithesis to the polished and modernized wealthy city surrounding it. Currently its owner, established developer Sheldon H. Solow, has plans to develop the site with luxury residential condominiums, which would result in the complete erasure of its 'vague' condition. This proposal to do nothing in New York City challenges the norms of Manhattan's urban practices, and asks the question: "How can architecture productively engage a Terrain Vague?