This article demonstrates that the spatial category of depth is crucial for understanding Aeschylus' Persians. Underground spaces are often symbolically represented in Greek drama not only on a vertical axis but also by the interior of the stage-building (skene). By investigating the connections between ‘interiority’ and ‘depth’, this article argues that the most economical and effective reconstruction of Darius' apparition is to suppose that he emerged from the interior of the skene, whose existence at this date is often disputed. The article furthermore analyses the multifaceted concept of the earth in the Persians, to suggest new ways in which underground, ground and interior spaces can be connected holistically to other spatial and natural imagery.