Picture this: rows upon rows of human skulls stacked neatly on wooden racks, bleached by the sun, staring out into the sacred courtyards of ancient Tenochtitlan. This isn’t a scene from a horror movie — it’s history. Meet the Tzompantli, one of the most chilling and misunderstood relics of Aztec civilization.

Welcome to a place where the line between the living and the dead feels paper-thin. A place where mist clings to the rocky earth, the air stings with sulfur, and volcanic vents hiss like whispers from beneath the ground. This is Mount Osorezan, often translated as the “Mountain of Fear,” one of Japan’s most spiritual—and strangest—destinations.