We currently face a baffling paradox. While since the fall of the Berlin Wall in 1989 a seemingly inexorable process of globalisation has been foreshadowing a peaceful and frontierless world, the number of walls across the world has been rising at a steady pace. Liberal and open societies buttressed by trade, international law and technological progress were supposed to implacably contribute to the erosion of frontiers and walls between nations. However, in a context of surging populist discourses, securitarian anxieties and identitarian politics as well as concomitant flows of migration alimented by climate change, conflict and poverty, nations have recently started to barricade themselves behind new walls.