Mass assembly on squares tends to be associated both with democracy and authoritarian as well as populist regimes (where assembly is connected to acclamation). The article elucidates the specific democratic functions of mass assembly, and how they can be facilitated both legally and spatially. In case of the former, it provides a critical analysis of indispensable core components of the right to assemble (which has recently been hollowed out in many jurisdictions); in matters of space, the article proposes characteristics of squares that might facilitate and represent different forms of democratic assembly (without claiming that such characteristics could ever guarantee democratic outcomes). Some recent empirical evidence for how squares have enabled the increasingly important phenomenon of “urban civic revolutions” is also discussed.