This study addresses the problem of designing an appropriate learning space or architecture for distributed online courses using net-based communication technologies. We apply Wenger's criteria to explore, identify and discuss the design architectures of two online courses from two comparable online Master's programmes, developed and delivered in two different educational cultures, Ireland (MIC) and Denmark (OL). The investigation will take the shape of a discussion of the 'walls of the learning spaces' of the two courses, with reference to Wenger's criteria and values for an appropriate learning architecture. In an earlier evaluation study, both courses were deemed to be examples of online learning communities of practice, despite their geographical and cultural diversity in contexts of development. The findings of the present study confirm and document several significant design elements of the two courses, which are stressed in the design criteria suggested by Wenger as being vital for community building.