The Huns, invading through Dariali Gorge on the modern-day border between Russia and Georgia in AD 395 and 515, spread terror across the late antique world. Was this the prelude to the apocalypse? Prophecies foresaw a future Hunnic onslaught, via the same mountain pass, bringing about the end of the world. Humanity’s fate depended on a gated barrier deep in Europe’s highest and most forbidding mountain chain. Centuries before the emergence of such apocalyptic beliefs, the gorge had reached world fame. It was the target of a planned military expedition by the Emperor Nero. Chained to the dramatic sheer cliffs, framing the narrow passage, the mythical fire-thief Prometheus suffered severe punishment, his liver devoured by an eagle. It was known under multiple names, most commonly the Caspian or Alan Gates. Featuring in the works of literary giants, no other mountain pass in the ancient and medieval world matches Dariali’s fame. Yet little was known about the materiality of this mythical place. A team of archaeologists has now shed much new light on the major gorge-blocking fort and a barrier wall on a steep rocky ridge further north. The walls still standing today were built around the time of the first major Hunnic invasion in the late fourth century – when the Caucasus defences feature increasingly prominently in negotiations between the Great Powers of Persia and Rome. In its endeavour to strongly fortify the strategic mountain pass through the Central Caucasus, the workforce erased most traces of earlier occupation. The Persian-built bastion saw heavy occupation for 600 years. Its multi-faith medieval garrison controlled Trans-Caucasian traffic. Everyday objects and human remains reveal harsh living conditions and close connections to the Muslim South, as well as the steppe world of the north. The Caspian Gates explains how a highly strategic rock has played a pivotal role in world history from Classical Antiquity into the twentieth century.