This article considers how networked large urban screens can act as a platform for the creation of an experimental transnational public sphere. It takes as a case study a specific Australia-Korea cultural event that linked large screens in Federation Square, Melbourne, and Tomorrow City, Incheon,1through the presentation of SMS-based interactive media art works. The article combines theoretical analyses of global citizenship, mobility, digital technologies, and networked public space with empirical analyses of audience response research data collected during the screen event. (...) The central argument is that large public screens can offer a strategic site for examining transformations in the constitution of public agency in a digitized, globalized environment. The idea of ‘aesthetic cosmopolitanism’ is finally proposed as a conceptual framework for understanding how new forms of transnational public agency in mediated public spaces might operate. (shrink)