The city would not exist as a modern urban society without the urban public domain. This is the central claim of a large number of theories of urban culture. After all, urban life is defined by the fact that we are forced to share the city with a multitude of strangers from disparate backgrounds and with diverse identities and interests. For this reason it is of great importance that there are public spaces where we encounter these “others”, are confronted by them and must relate to them. In each of these theories, the urban public domain in which people negotiate their everyday practice, cultural identity and political ideals has a physical character: it takes place on the agora, the boulevard, the street or in the coffee house.

However, at the beginning of the twenty-first century digital and mobile media are beginning to play an ever-greater role in the spatial experience of urban life and this has consequences for the manner in which the urban public domain functions. Indeed, I would venture that it is now questionable whether the concept of the urban public domain is still meaningful now that the interfaces of digital media are beginning to play a large role in the ways in which people relate to each other in cities. It is my contention that, partly for this reason, the term interface will have to play a central role in the theory of urban culture. The interactive video installation Body Movies – Relational Architecture 6 by the Mexican artist Rafael Lozano-Hemmer makes clear how this works.

Body Movies – Relational Architecture 6 was shown in Rotterdam in September 2001 as part of the city's celebrations as Cultural Capital of Europe. The work by the Mexican artist Rafael Lozano-Hemmer consisted of a nocturnal shadow play generated by passers-by on the immense side wall of the Pathé cinema complex on the Schouwburgplein (see figures 12 and 13). In recent years Body Movies has come to be seen as a canonical project within the critical discourse around digital and interactive media. In this contribution I intend to demonstrate, partially on the basis of some of these commentaries, how Body Movies has made an important contribution to the debate about the urban public domain. In particular, the work questions the impact of digital and multimedia technologies on urban culture.