Following the devastation of the northern Iraqi city of Mosul by the Islamic State (IS), UNESCO launched a project to ‘Revive the Spirit of Mosul’. This article critically reflects on this UNESCO-led project, drawing on 47 interviews with Syrians and Iraqis, as well as documenting the implications of UNESCO’s efforts in earlier (post-)conflict heritage reconstruction projects in the Balkans, Afghanistan and Mali. Specifically, this article focuses on two sites in Mosul, both deliberately destroyed by the IS and both nominated by UNESCO for reconstruction. The data analysed reveal that heritage reconstruction projects, especially in complex (post-)conflict environments such as Iraq, requires ongoing, nuanced and careful engagement with local populations to succeed. Failure to do so leaves both local people and their heritage sites vulnerable to renewed attacks and therefore ultimately undermines UNESCO’s broader mission to foster peace.