In this paper we report on studies we conducted focusing on the use of Augmented Reality to annotate real sites with relevant archival content. This is an interdisciplinary study of novel interactive technologies and supportive platforms such as geolocation-navigation and contextual digital augmentation of archival material in public spaces. We involved community volunteers, experts and public in a participatory heritage initiative. We designed an experience that supported a multi-platform participation, via an online geo-tagging portal and a mixed reality navigational experience. In an iterative design process we explored the use and preference of mobile devices, the controlled design of digital content anchored to real sites and the use of AR to support urban narratives. This was achieved by conducting a series of user walkthroughs with recruited participants and workshops with local experts related to the case studies. In this paper we stress the importance of situating urban experience of digital archives and stories in the actual locations of the events they represent as to better support immersion, enhance place experience and reinforce situated learning. Our work contributes to the design of hybrid spatial experiences in the city context that relate to local memory and culture.