The Syrian civil war and the international campaign against the Islamic State, also known as ISIS or ISIL, have produced wholesale devastation, which journalists, national authorities and international agencies are still trying to assess. In some parts of Iraq and Syria, the destruction is visible and almost total: cities such as Raqqa, Mosul and parts of Aleppo have been left in ruins. These circumstances have raised awareness of a longer-term challenge: many countries facing protracted conflict or recovering from it face rapid and unmanaged urbanisation. As a result, a profound rethink of responses to armed conflict in cities is in motion, in terms of both emergency humanitarian action and longer-term policies for security, rehabilitation and development. There is a growing consensus among practitioners that responses to armed conflict in cities should extend beyond short-term aid and lay the groundwork for coping with the longer-term challenges posed by urbanisation.