Valuing the subterranean: The tunnels of Gibraltar in war and in peace

This article argues that value can be a key concept for bridging between geopolitics and economic geography, providing a historicised account of a subterranean geopolitical space as it shifts from a valuation regime focused on strategic use value to one focused on commercial exchange value. This argument is pursued through an empirical investigation of the tunnel system within the Rock of Gibraltar, tracing how they have been valued differently in different times due to technological and geopolitical change. Empirically, the article traces the creation of the tunnels by the British military from the 18th century until the mid-late 20th century, paying careful attention to the role of materiality, geology, and the broader techno-political assemblages that enabled and sustained that investment (until they no longer did). Crucially, the empirical investigation continues into the present, as the geopolitical value of the tunnels has largely been replaced by efforts to extract commercial value from them. While most of the tunnels have not found commercial use, the paper finds that the most successful commercial enterprises have used them in ways congruent with their fortress origins and the materiality of the Rock. The article concludes by arguing that the value of subterranea is imagined at the point of initial human investment, but once that investment materialises the value emerges from a wider relational space – drawing together the geology of the site, the people who work there, and broader circuits of empire and capital.