The Flash-back city workshop series explores the power of collaboration and collective imagination: here the built environment is playfully reimagined, not as a blank canvas, but one rich of collective meaning and narrative. Through a rigorous process, participants collectively draw, explore and develop an urban fabric based on crowdsourced associations and memories on a room sized canvas. The base drawings are tailored to the specific context and allow to explore cities in an artistic, imaginative manner. This immersive process results in propositional, collaborative drawings and urban mind maps which are as diverse as the participants: often, our workshops unearth deeper insights into the relationship between local communities and their immediate natural and built environment. This is when collaborative drawing shows its potential as a valuable resource for future decision making processes in the built environment – an inclusive co-creation method which prompts creative discourse.