One of the key transformations over the last decades is the rise of a whole new type of economy, one that finds in cities its ideal operational space. This has meant competition for housing and the sharp rise in the price of housing. There was a time when much economic activity was outside cities and in fact cities had become poor, with New York officially bankrupt. The common expectations was: cities are finished. But then a new economy emerged and it needed above all concentrated and highly diverse urban space. This brought about the expelling of modest income households from much of central urban space. A new division with its own frontier has emerged out of this transformation.