In this lecture open to those attending the Cambridge Alumni Festival, Dr Wendy Pullan, explores the role of wall structures within the conflicted urban environment. The separation barrier in Jerusalem has galvanized public opinion, both in its role as a hard barrier inside a divided city and as the visible ‘tip of the iceberg’ that reflects only a fraction of the political and military regime supporting the occupation. Walls of this sort are becoming more common, even in an age of high tech and digital security. This lecture will consider dividing walls in Jerusalem and several other settings. It will acknowledge the wall’s political status but focus on issues to do with the iconicity of such a structure, including its power in situ in the human landscape, in the media and in its existential meanings.