The SIMILAR-CITIES project is a joint effort between INRIA, CSTB and Allegorithmic to enhance the visual appearance of virtual cities, using procedural methods. Our key insight is to replace the numerous textures used to faithfully render large virtual cities by procedural equivalents. These procedural textures are thousands of times smaller but can still be quickly generated whenever required by the rendering engine. Our every-day tools for this research are procedural texture generators, texture synthesis by example, texture streaming algorithms and image processing tools.