An increasing number of people want to live in city centres, where space is limited. This causes architecture to grow vertically, creating new worlds on top of old roofs. Examples of this, seen on the Rhine riverbank in Cologne, Copenhagen and Graz, show how charming these new living spaces can look. Eight roofs from around the world are examined in detail, each covered with different materials: Adam Kahn uses wood shingles for his 'swimming visitors' centre; Diller Scofidio designs a park on top of a restaurant's green roof; Hopkins Architects gives the steel supporting frame of the Olympic cycling stadium a dynamic swing; Zaha Hadid wallows in Glasgow, with curves made of zinc sheeting and Jürgen Mayer H. is under huge umbrellas in the Spanish sun. In the chapter »technology« the complex supporting structure of the polyurethane-laminated, veneer-layered timber construction will be explained in detail.