The Mediterranean landscape consists of spaces shaped by water systems, such as lakes, rivers, and coastlines, whose border configurations create a discontinuous and non-systematic linear infrastructure. Our article starts from a key premise: the heterogeneity of water sites in Mediterranean landscapes results from processes involving the accumulation of shared memory and opportunities triggered by a mixture of events. This characteristic is an undeniable but non-binding fact. Given this premise, observing this specific category of places within the Mediterranean imaginary is essential, focusing on the quantitative aspects of their morphological characteristics, measured by the density of urban structures in relation to the presence of empty, interstitial, and potentially connective spaces. This can be summarized as an indicator of their porosity and permeability: a dual category to be analyzed through a new investigative model that assesses the capacity of water spaces as infrastructure to foster new symbiotic configurations between urban and natural elements. Control (a fair comparison between cause and effect) and systematic investigation are applied by simplifying the physical boundary into a double-faced linear sign between city and sea, serving as a descriptor for scientific models of anthropic and natural components. The line, not understood rigidly in geometric terms, is assumed as a conceptual background and domain, explored through various partial interpretative models that operate within the design process. The aim of this process is the gradual transformation from line to space, from space to place, and from place to landscape. Using Messina as a case study, our research seeks to provide a specific perspective on Mediterranean urbanity, in which the physical element of the water’s edge holds significant potential for urban projects and future transformations.