Chapter 11 of Earthopolis: A Biography of Our Urban Planet explores cities’ role as creators and creations of the political revolutions of the late-eighteenth-century Atlantic world. It argues that traditions of urban “freedoms” going back to the revival of European cities, imperial conflict throughout the world between regimes based in London and Paris, restive settler colonial cities in the Americas, and the Atlantic economy’s reliance on enslavement made the Atlantic into the world’s first “cauldron” of modern revolution. It traces the close connections between the American Revolution that started in Boston and the French one in Paris, while investigating the ways revolutionaries used the spaces of a cities designed for colonial or authoritarian control to overthrow otherwise all-powerful-seeming regimes, replacing them with structures designed for democracy or People Power.