Studying the future seems a mission impossible, since both the appearance of the future and its underlying dynamics are unknown and unknowable. Nevertheless, the future is being studied by professional futurists. So, professional futurists seem to have found ways to structure 'the unknown'. The question is, then, how do they do this? Over the years, professional futurists have developed several types of techniques and methods to structure thinking and discussing the future. The scenario-axes technique, which aims to align divergent perspectives on how the future may unfold, is one such structuring device. In the past 2 years, we did ethnographic research at the Netherlands Institute for Spatial Research (RPB) and followed professional futurists constructing and applying scenario axes in their scenario projects. Our observations illustrate how the scenario axes are practised by professional futurists and show that the scenario axes do not function as a unifying structure fostering alignment of different perspectives in the way that scenario theorists and practitioners often suggest. Instead, not one, but three different applications and interpretations of functional meaning of the scenario axes co-existed: the scenario axes as a 'backbone', as a 'building scaffold' and as 'foundation'.