The skulls of around 150 human sacrifice victims have been unearthed in a field in central Mexico. It's one of the first times such a large discovery has been made outside a major pyramid or temple complex.

"The interesting question is, why are we seeing this kind of sacrificial act that we often associate with something like Teotihuacan or a big center. Why do we see this … in a place that's not associated with these cities?" Georgia State University archaeologist Christopher Morehart told AP. He found the skulls in Xaltocan, a farming village north of Mexico City.

According to Morehart, the Xaltocan mound "is like a bump in the landscape that you could really easily walk over and not know you're standing on it."

The heads appeared to be carefully deposited in rows or in small mounds, mostly facing east toward the rising sun, sometime between 660 and 860 A.D.

Physical anthropologist Abigail Meza Penaloza of the Institute of Anthropology at Mexico's National University, whose team was cleaning and assembling the skulls, also reportedly confirmed that it was the first find of its kind, both in terms of the location, and the kind of decapitations carried out. She told AP mass sacrifices had been documented at temple inaugurations of temple closings, but not in the middle of fields.

She says it was unusual that the skulls came from a varied population, including people who practiced cranial deformation and others who did not, as opposed to more homogenous groups of sacrifice victims found in the past.

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