The paper wants to present an alternative model for the design of urban corporate identity and city branding. In the first part the paper presents traditional and famous case studies of city branding and in the second part it presents: an example of completely different design approach; our didactic methodology and the experimental projects developed by students, in the field of Communication Design for urban environment. In our design approach, the graphic marks, the logos, is designed starting from the city details as emerging signs related to the complex urban identity. The urban sign (several kind of trace) is very different to the traditional city brand that is a visual synthesis of meanings and values. The didactic results want to bring attention to the revaluation of the urban signs as traces on the "skin of the city". The goal of the our didactic course is to design models of corporate identity and city branding starting from what the city shows about its details; so the trace, the minimal signs, becomes bearers of meaning. The didactic projects, developed in our course, want to represent the image of the city through unconventional point of view. So these graphic marks and logos are, of course, "visual summaries" of city values, but these are not related to the city stereotypes that instead are usually used for city branding. The urban traces become the starting point for the creation of logos and communicative artifacts. The method used, starting from the analysis of the basic graphical elements, it consists of different phases of design. The practice phases starts from a photographic collection of urban "vertical and horizontal traces" gathered on the streets and walls. The final goal it is the definition of a logo that merges together a strong concept and visual elements. The graphic marks and logos designed by students show different aspects of city's identities. In fact the marks, gathered in a collection, show an "atlas of signs": traces that express the "character" of the city.