Transformative urbanism: The city is always evolving but change is not always synonymous with transformation. This week we explore how the urban environment has gradually altered, most of the time thanks to us – ordinary citizens. We discuss the concept of participatory placemaking, head to Toronto for a chat about designing urban transformation and stop by New York to look at some of the changes the city has gone through. Plus: we meet the real-estate firm investing in “transformational developments” in Los Angeles as it tries to save architectural relics from the 1920s.