The early success of the Museum of London’s Streetmuseum—an augmented reality app that overlayered images from the museum’s collections onto the streets of London—spawned many imitations. The appeal of “taking the museum to the streets” was undeniable: mobile media offered the potential for cities to breathe new life into urban heritage by putting it in conversation with the vibrant streetscape. Users, in turn, were offered a kind of techno-mediated time travel, invited to see and hear the city’s past, and walk the streets as they were. Apps like these are a type of “locative media”: mobile media that enable users to encounter digital content in “real” places (see Lynch, Locative Tourism Applications: A Sensory Ethnography of the Augmented City, Routledge, London, 2023). However, the city street is far from a neutral exhibition space. As they weave locative narratives into the streetscape—producing the simultaneous city on foot—the app user’s “glimpse into the past” is often rife with felt contradictions and alternative histories. Based on sensory ethnographic research with locative apps in seven cities (Dublin, Derry, London, Edinburgh, New Orleans, Melbourne, and Christchurch) this chapter considers how locative media as a form of heritage placemaking can multiply our imaginaries of what the city was, is, and will become.