Thirty years from the fall of the Berlin Wall, new global tensions are polarising our world – and our cities feel more divided than ever. From today and for the next four weeks, our international film series will tell the stories of five cities that reflect these divisions in surprising and troubling ways

Thirty years ago, a rapt world watched the unfolding of one of the great city stories of all time. Every hammer blow chipping away the imposing grey blocks of the Berlin Wall, which had come to embody global geopolitical divisions, seemed to herald a more united future.

Since then, however, our world has fractured anew and our cities feel more divided than ever. When the Berlin Wall fell, there were two border walls in Europe; now there are 15. Nor is this fracture merely physical: many cities are havens of wealth and privilege for those who hold the access codes, hives of struggle and poverty for those who do not. Wherever I travel to report I have always been struck by how different people can have such contrasting experiences of the same city – and it’s no different at home, in my neighbourhood of Camberwell, south London, where upscale coffee shops and gang violence occupy the same stretches of road.