When Mexican police found a pile of about 150 skulls in a cave near the Guatemalan border, they thought they were looking at a crime scene, and took the bones to the state capital.
It turns out it was a very cold case.
It took a decade of tests and analysis to determine the skulls were from sacrificial victims killed between A.D. 900 and 1200, the National Institute of Anthropology and History said Wednesday.
The Aztecs and similar tribes were brutal, vicious, and wicked:
[...] experts said Wednesday the victims in the cave had probably been ritually decapitated and the skulls put on display on a kind of trophy rack known as a "tzompantli." Spanish conquistadores wrote about seeing such racks in the 1520s, and some Spaniards' heads even wound up on them.