The influx into cities is leading to increased density and thus to growing pressure on inner-city open spaces. In dealing with the resulting deficits, the conversion of infrastructural areas lends itself. 22 examples illustrate the meanwhile very broad spectrum of this newly created type of open space. The focus is on projects that transform existing 'grey' infrastructure into new 'green' infrastructure, such as road overlays, transformations of traffic routes and converted spaces underneath bridges.

From this selection, the qualities of eleven best practice projects are presented in more detail, in particular the design approach and the urban integration. Implementation processes, forms of participation and methods of quality assurance are also explained.