Archaeologists in Peru have uncovered what may have been the world’s largest mass child sacrifice, National Geographic reports in an exclusive story. Residents of Huanchaco first noticed human bones in 2011, in coastal dunes near the capital of the former Chimú empire. Over the next 5 years, archaeologists supported by grants from the National Geographic Society uncovered the remains of more than 140 children aged 5 to 14, as well as 200 young llamas, dating from about 1450 C.E. The llamas and the children had cuts to the breastbone and dislocated ribs—suggesting that their hearts may have been removed. The scientists say the children were likely victims of a ritualistic killing in response to extreme weather that devastated Chimú’s agricultural infrastructure.