Hand-carved arrowheads and jagged spears made of obsidian, a sharp rock formed by volcanic magma, are remnants of vast prehistoric trade networks that once cut across western North America. New ...

At a depth of 2.80 meters, inside the offering box, 59 obsidian blades and seven knives were found, along with three blocks of copal, which testify to a ritual likely of self-sacrifice performed by ...