According to an exclusive report by National Geographic which was released on Thursday, the skeletal remains of more than 140 children and 200 baby llamas were found in Peru, country's northern coast.
It's estimated that the children ranged from about 5 to 14 years old, with the majority between the ages of 8 and 12, according to the magazine. The llamas, all younger than 18 months, were buried facing the Andes to the East.
The condition of the remains suggests the children had incurred cuts to the sternum and rib dislocations for the removal of their hearts.
This is the second mass grave found in the area: another site was uncovered in 2011, with 42 children and 76 llamas unearthed outside a 3,500-year-old temple.
Incidents of human sacrifice among the Aztec, Maya and Inca have been well documented throughout history but the discovery of such a large-scale child sacrifice event is unprecedented in the Americas, if not the entire world, National Geographic reported.
The site was located on top of a cliff facing the Pacific Ocean in La Libertad, a northern region where the Chimu civilization arose, an ancient pre-Columbian people who worshipped the moon.
"Perhaps the people offered to the gods the most important thing that existed in their society, that is children who represent the future", said Professor of archaeology, Gabriel Prieto.
First discovered in 2011, excavations on Huanchaquito-Las Llamas concluded in 2016. The researchers think the adults may have performed the ritual killings then were executed shortly after.
High sea temperatures caused by the El Nino effect would have disrupted marine fisheries in the area, while coastal flooding could have overwhelmed the Chimu's extensive infrastructure of agricultural canals, the publication said.
"It is ritual killing, and it's very systematic", Verano told National Geographic. But the archaeological record suggests they succumbed to an Incan invasion only a few decades after the sacrifices occurred. The rains kept coming.
Based mostly on proof from layers of dried mud, the report states it is believed that each one the human and animal sacrifices happened on the similar time. Human sacrifice has taken place in every corner of the world at one time or another in our history, although the mass sacrifice of children is very rare, actually nearly unheard of to most scientists. There are even skid marks in the sediment indicating places where the sacrificial victims were reluctant to participate.
"But it's actually a much more complicated attempt at negotiation with those supernatural forces and their manipulation by the living".