In recent years, there has been an explosion of data. One approach to big data is visualization. Data can be transformed in aesthetic ways to reveal its truths and to make it appear accessible to humans. What often gets ignored in visualization is the context of consumption of visualizations. Increasingly visualizations are showing up on data walls in public spaces. The scale of data walls and the types of spaces where they are installed change the interpretation and rhetorical affordances of visualization, and that is what this paper is about: exploring the new visual space of data walls through speculative design prototypes.