I was also reminded of another famous military wall constructed in a remote mountain landscape to keep a daunting adversary at bay, the so-called “Alexander’s Gates,” a monumental—and entirely mythic—architectural project allegedly built by Alexander the Great in the Caucasus region to keep monsters out of Europe. This myth was the Pacific Rim of its day, we might say.
I first encountered the story of Alexander’s Gates in Stephen T. Asma’s book, On Monsters.
Alexander supposedly chased his foreign enemies through a mountain pass in the Caucasus region and then enclosed them behind unbreachable iron gates. The details and the symbolic significance of the story changed slightly in every medieval retelling, and it was retold often, especially in the age of exploration. (…) The maps of the time, the mappaemundi, almost always include the gates, though their placement is not consistent.