MEXICO CITY, MEXICO—Anthropologists studying remains from a recently unearthed Aztec tzompantli, or trophy skull rack, were suprised to discover skulls belonging to women and children, according to the BBC. Built between 1485 and 1502, the rack was thought to have been used by the Aztecs to display the heads of enemy warriors who were ritually sacrificed. "We were expecting just men, obviously young men, as warriors would be, and the thing about the women and children is that you'd think they wouldn't be going to war," says biological anthropologist Rodrigo Bolanos of the National Institute of Anthropology and History. "Something is happening that we have no record of." More than 600 skulls have been found, and the tzompantli is still being excavated, so archaeologists expect to find more. To read in-depth about the excavations, go to "Under Mexico City."