The Activist City highlights different forms of civic protest: political, urban and architectural activism. Political activism mostly takes place in the city, urban activism has the city as its topic. ‘Architectural activism’ sounds like a paradox as architecture is on the side of money and power and activism opposes these. But over the last years we have seen architects engaging with the skills of their discipline within urban activism and even see forms arising of what could be called ‘activist architecture’. The first part of this book evokes in several essays the broad context of activism today, with a focus on ecology and the commons. The second part contains an introduction to the idea of activism as democracy in the city, focussing on the three different shapes it takes. The final part reconstructs the struggle for road safety in Brussels (a constant reference point in the book) as a situated commitment spanning over years as well as a concrete form of urban activism. The authors, who have been teaching and writing together for years on these topics, consider activism as an important element in bottom-up urban democracy and the struggle for a more social, just and sustainable society.