This article is an introduction to how architecture's context and conditions can be understood as signaletic with reference to Gilles Deleuze's concept of the signaletic material. The understanding of architecture's signaletic material addresses the process of becoming through the potentials of context and the requests towards function and programme, as well as through the methods for creating architecture—all seen as conditional components of a specific work of architecture and, consequently, as part of the signaletic material. A visit to the New Acropolis Museum is analysed to discuss how the potential of the in-between encounters of architecture, context and the experiencing subject can be part of the signaletic material and the process of becoming. This potential is actualised, for instance, in relation to the movement through the museum. The museum architecture affords experiences on potentially several levels spanning from the most pragmatic and functional use of the building as exhibition space, restaurant, book shop, etc. to the awareness of being part of an architectural intentionality as a moving body, a contemplating viewer and as a perceiver of relations between the museum building and its historical and geographical context. In the article the term “visitor” is used to emphasise this complexity of experiential potential that is made accessible by the museum's architectural design.