Territorial boundaries are one of the defining features of sovereign statehood. States assert absolute authority over what goes on within those lines and are expected to make almost no claims beyond them. Why is political organisation defined in this particular way? Without the ideas and practices made possible by one visual medium – mapping – states would look very different today. Cartographic techniques and images, in short, played a key role in the origins of territorial states and continue to reinforce the dominance of this form of political organisation and interaction.