A team of international scientists has utilized Holographic Muon Imaging to discover a hidden network of hydraulic reservoirs beneath the 2,500-year-old Citadel of Erbil in Iraq. The non-invasive technology detected density anomalies that revealed massive stone-lined chambers designed to collect and store groundwater, predating many known Roman-era water-management systems in the region.
These subterranean structures provided the citadel with a secure water supply during long sieges and periods of extreme drought. The engineering feat demonstrates the advanced urban planning of the ancient Mesopotamian inhabitants, and the newly mapped data will assist heritage authorities in the ongoing structural stabilization of this UNESCO World Heritage site.