Contemporary architecture and urbanism concern everyday life in multiple contradictory ways. Floating between alienation and hope, post-industrial and other interstices often hold beautiful and poetic aesthetics of decay, attracting people driven by curiosity or political causes, stimulating the creativity of these spatial environments. Driven by struggles against standardised and authoritarian urban contexts, a search for Alternative Cultural Spaces (ACS) as concrete contemporary examples of spatial, convivial, creative and political experiences is the main objective of this research. Case studies selected in Lisbon, Ljubljana and Geneva (cities affected by different physical conditions, particular histories and general urban and economic contexts) focus on the years 2005-2015, but also look back to the 1970s. Based on participant observation and other qualitative methods, such as photography, sketching or mapping, the research gives a big importance to visual and spatial production and analysis, in order to reflect social and political engagement as part of wider urban contexts. Considering that the "aesthetics of resistance" of the ACS are influenced by practices of counter-cultures and avant-gardes (DIY, collage, site-specific), we believe that these "re-architectures" (re-use, re-habilitation, re-conversion) are also architectures of resistance (to mainstream, standardised and normalised spatial practices and to abandonment and negligence). However, these alternative aesthetics have become trendy over the last few years, becoming no longer exclusively used by leading resistance or subversive actions but being object of recuperation and consequently of instrumentalisation by neoliberal strategies. Culture and creativity are now at the core of urban planning, based on competitive processes and aiming at economic profit. Three kinds of aestheticisation processes were identified: alternative experiences born from grassroots projects, built over time; top-down processes that force the projects and their spaces to adopt restricted norms in order to assure survival; processes born with the projects designed, recreated and guided by a for-profit concern. The last two cases contributively reduce the diversity of urban experience and control creativity, through annihilation or a forced ambiance. This thesis shows that the visual expression of Ljubljana's alternative aesthetics of resistance is stronger than Lisbon's, and that Geneva's is suffocated by normalisation processes over recent years. The way a spatial ambiance is perceived by the user of a particular space depends largely on the mode of production of that same space, and on the primary intentions existing behind the creation of a particular design or construction, varying from mainstream and institutional approaches to the most subversive ones. Compromise is present and visible through the aesthetics of an ACS. Logics of urban-spatial occupation highlight the importance of the squat movement in Geneva, of the counter-cultures in Ljubljana, and of the fragmented networks of ACS in Lisbon. They also show how ACS propose a cultural network that is complementary to the mainstream one. Besides, either ACS move in the city or they experience a process of aestheticisation. One and another are directly related with survival strategies. Assuming a dialectic perspective of resistance and compromise, this thesis exposes the complex, hybrid and ambiguous dimensions of ACS.