This book investigates the hidden physical infrastructures behind the digital world. Data may appear immaterial, but it relies on extensive global networks: the extraction of raw materials, the deployment of thousands of undersea cables, and an exponentially growing number of energy-intensive data centers. While these data infrastructures shape global economies and politics, they truly do far more by profoundly impacting local communities, ecosystems, and labor conditions—realms so often rooted in (neo)colonial structures of exploitation. The contributions in this volume call for greater transparency, critical awareness, and care toward the material foundations of the data economy—as essential conditions for more equitable and accountable digital futures. Bringing together voices from architecture, media studies, technology, art, and political theory, City in the Cloud – Data on the Ground explores the elemental, spatial, and temporal dimensions of the architecture of data. The volume maps the costs of the data economy—ecological, social, and political—and opens up perspectives for rethinking digital infrastructures in the context of planetary resources, justice, and long-term responsibility.