From the favelas of Rio to the slums of Nairobi to the streets of California, activists are working to make city planning more healthy and equitable. By knowing their history and where they came from, activists and governments are aiming to promote greater equity from neighbourhoods to the nation. Yet, as all the cases here suggest, the work is incomplete and ongoing. This contemporary reality reflects the history of modern urban health; the state, professionals and activists struggle to understand what makes places and populations more healthy while acting with incomplete information. Healthy city planning is a politics and process of engaging with all aspects of city governance, but where the expertise and experiences of civil society organisations is at the centre. HCP never was, nor currently is, primarily about physical plan making.