Last year archaeologists in Peru announced the discovery of a centuries-old ritual massacre, at a site they believed was the largest known case of child sacrifice ever found. Buried beneath the sands of a 15th-century site called Huanchaquito-Las Llamas were nearly 140 child skeletons, as well as the remains of 200 llamas. While the reasoning behind the gruesome mass murder of the boys and girls — who were only between the ages of 5 and 14 — cannot be definitively determined, the researchers now say the act was done out of desperation in response to a disastrous climatic event: El...