This chapter considers the poetics of Roman imperial expansion in three dimensions. It investigates the depth and density of straits and clogged waterways—paradigmatically the Hellespont—in Latin poetry from Catullus to Statius, arguing that such spaces become laboratories for the ways in which poetic and military power is amplified in imperial texts via restriction, contraction, and pressure rather than by expatiation. The aim here is to go beyond recent critical appraisals of straits on either side of the Black Sea as simply representing an ‘overcrowded literary tradition’, in which expectations are confounded, bellicose epic is mitigated or postponed, and Alexandrian principles ironically reconfirmed. By the second half of the first century CE, as Roman poetry gets to grips with and reshapes discourses of empire, the spatial metaphors that underpin its evolution are smashed apart.