Large urban centres and metropolitan areas in particular are acquiring increasing importance in the European spatial and economic system; they are the derivatives of the extensive urbanization which occurred during the transition phase from manufacturing to service industries. Urbanization in Greece took place much later than in the cities of the European north, and at much a faster rate. The special character of the urbanization process in Greece has contributed not only to the economic growth but also to social and political integration. Poverty, until the '70s, was predominantly a rural phenomenon. Although, according to the evidence, until the '80s it remained so, it is at the same time increasingly associated with urban conditions. Public housing complexes are very few and 'suburbs' are of a middle class character. The 'popular' suburbs of metropolitan regions are extensive areas which have developed spontaneously mostly through illegal practices of new migrants.