International Law, we are often told, ‘moved to Institutions’ in the early twentieth century. While recent literature has (masterfully, to be sure) explored the intellectual trajectories of some of the leading lawyer-diplomats or legal doctrines entangled in these international organisations, most accounts divorce their analysis from the seemingly banal histories of the ‘buildings, staffs, and letterheads’. This is particularly true for the history of the interim headquarters of international institutions. For the towering edifices specially erected to host these organisations, just like Rome, were not built in one day. For this reason, the early years of these institutions were shaped by the spatial constraints that their improvised and temporal dwellings imposed on them. For that reason, in this piece I shed light on the interim function of the Hotel National (1920–1937) and the Lake Success complex (1947–1952), as, respectively, placeholders for the League of Nations and the United Nations. By situating the everyday geographies of international law-making in these two precarious and unstable venues, I explore the tensions and hierarchies embedded within parochial modes of organisation that claimed the mantle of the international.