The aim of this work is to analyse the open spaces with special attention to those that enable the permanent or eventual organization of open air markets. We choose to study the spaces associated with cultural practices because we believe that these activities leads to the re-creation and re-conceptualization of new spaces. The work adopts a broad understanding, seeing urban design as more than simply the physical or visual appearance of development, but also as an integrative and integrating activity – and as such, it should be produced for people to use it. Some authors state the evidence of the effects of fragmentation in contemporary cities and the establishment of new patterns of urban perception and appropriation. Although it is true, we call attention to the persistence of some structures, such as the open air markets that remain full of meaning in the urban life, even though they had been constantly modified. We also believe that these permanences play a very important role in the maintenance of the urban life and promote the emergence of new relations and spatial experiences. In order to analyse the many aspects of the urban form of these spaces we compare different ones, where these activities take place, observing three different dimensions: morphological, perceptual and social dimensions. The comprehension of these dimensions associated to some hidden rules – which are found very frequently in open-markets - make evident that urban form and its uses can not be studied separately. Understanding the contemporary urban life as a result of intense mobility and interconnectivity between spaces, the open air markets appear as a relevant promoter of movement and urban vitality. The open air markets creates a very specific urban context, with diverse interests involved that requires a new comprehension of urban morphology and a development of a new thinking on the practice and process of urban design.