Alessandro F. Rotta Loria studies the world beneath our feet––the underground. His talk delivers an intense emotional and intellectual experience about the urban underground, unveiling a silent threat that simultaneously represents a massive opportunity for the clean energy transition of cities, before we run out of time. Dr. Alessandro F. Rotta Loria is the Louis Berger Junior Professor at Northwestern University, where he directs SOIL – the Subsurface Opportunities and Innovations Laboratory. He is also the co-founder of GEOEG and enerdrape. His work is centered on the subsurface and is dedicated to fostering the renewable energy transition, decarbonizing the built environment, innovating infrastructure, and conserving the environment through underground solutions. His endeavors aim to address pressing challenges and opportunities for cities and territories: from subsurface urban heat islands to sea-level change, and from geological energy harvesting and storage to the sustainable construction and preservation of civil infrastructure. Rotta Loria’s work empowers the underground in support of human activity—on Earth and beyond. His studies have culminated in the publication of one book, two book chapters, two patents, and more than 100 publications in scientific journals and conference proceedings.