June 4, 2008This circular plaza holds possible evidence of human sacrifice at the 4,000-year-old Peruvian archaeological site of Bandurria, thought to be one of the oldest urban settlements in the Americas.

Human remains have been found at the site before. But only recently have scientists discovered human bones bearing what could be the signs of ritualized violence. (Read full story.)

If laboratory analysis confirms that hypothesis, it would upend theories that the so-called Pre-Ceramic period (3000 B.C. to 1800 B.C.) was largely free of ritualized killings.

It is a truly incredible site, regardless of how the recent human remains come to be interpreted, said Shelia Pozorski, an anthropologist at the University of Texas-Pan American.

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