The "Tensions of Europe" network investigates the history of 20th-century technology along three main lines: the linking of infrastructures, the circulation of artifacts and services, as well as the circulation of knowledge. Although intended for the analysis of disparate phenomena in the history of modern Europe, these three dimensions appear particularly well suited for a discussion of the complexities of the technified city and urban life. The modern city is everywhere penetrated by infrastructual systems: traffic machines on its surface, communication networks in the air, and energy systems underground. Or, what about artifacts (goods) and services-has their intensive circulation not been a defining characteristics of urban economic life since time immemorial? And, the circulation of scientific and engineering knowledge in all possible forms is certainly a further typical phenomenon in urban settings-regardless of whether a city houses a university or not.

Taking for granted that the three dimensions are suitable for an analysis of the modern city, the task of the CITY research group within the ESF-financed "Tensions of Europe" network is to develop this framework further. In the first instance it will be necessary to pose the question to what extent European cities differ from other "villes contemporains" along the lines just sketched. Why, for instance, does it seem to be the case that European cities have linked their infrastructures in the area of public transportation more successfully than comparable cities on other continents? Furthermore, why is it the case that European cities have organized the circulation of artifacts and services in particular ways, and that these traditional ways appear to be threatened by a kind of "mall" culture at the turn of the 21st century? Or, has the European city-due to historically generic structures-developed particular forms for the dissemination and spread of knowledge and information? In other words, do the dimensions here proposed enable a better understanding of the peculiarities of the European city?