This project explores the international foundations of one of Latin America’s most ambitious urban infrastructure undertakings: Mexico City’s Deep Drainage System. Initiated in 1970, this vast subterranean network was not solely the result of domestic initiative, but also of sustained scientific and technological cooperation between the Global North and the Global South. The research aims to examine how advanced soil mechanics and geotechnical engineering developed in Cambridge were appropriated by Mexican engineers and became central to addressing Mexico City’s chronic flooding. To do so, it will draw on primary sources housed in institutions affiliated with the Consortium for History of Science, Technology and Medicine, including the Rockefeller Archive Center, MIT Distinctive Collections, and the Harvard University Archives. By foregrounding transnational knowledge exchange and wartime diplomacy, the project contributes to science and technology studies, while reassessing the role of international cooperation in shaping large- scale subterranean infrastructure in the Global South.