This paper focuses upon alterity and how we can more fully embrace intimations of otherness in our dealings with prehistoric monuments. Taking as its inspiration recent attempts to explain such structures, and the landscapes of which they were part, it makes two arguments. First, that while ethnographic analogies offer a vital point of departure for thinking through the possibilities raised by alterity and otherness, we may well have been overlooking a rich set of data—derived from careful excavation and painstaking metrical analyses—that has been sitting in front of us for a very long time. Second, despite over a decade of sustained critical debate, we seem remarkably timid when it comes to seeing where these data might take us. Through the lens of two Late Neolithic stone circles from southern Britain (one big, one small), research into measurement units and alignments is allied with recent excavation and survey data in order to explore ideas of hybridity, nomad-geometry and the arresting/manipulation of time and motion. Placing these glimpses of alterity front and centre, they are then used to establish new starting-points for the interpretation of these structures.