This essay reflects on ephemeral artistic practices in the contemporary city and their critical capacities in the face of the alienation, insecurity and fear that we feel in the public space. We live in an atmosphere of anguish in today’s liquid society. Our relationship with the Media, mainly digital, with the public space and with knowledge, is mediated by an ‘economy of attention’, which reduces space by expanding time. How do architects and artists answer these questions? Based on artistic interventions in the urban space, we intend to verify how their approaches/installations contribute to critical thinking in the face of contemporary environmental, political and social circumstances.