The cliff is located just outside the northwestern coastal city of Trujillo, Peru's third largest city which today has 800,000 inhabitants.
The area used to be the capital of the Chimu Empire, which forged the second largest empire in the history of the ancient Andes between the 12th and 15th centuries before they were conquered by the Incas, according to the encyclopedia of ancient history.
Calling it a "remarkable discovery", Jeffrey Quilter, the director of the Peabody Museum of Archaeology and Ethnology at Harvard University said the site provides "concrete evidence" that large-scale sacrifices of children occurred in ancient Peru.
Current research in Peru, officially called Huanchaquito-Las Llamas, conducted by an global team funded by the National geographic society.
In addition, near the city of Trujillo also were found the remains of 200 young lamas who, apparently, was sacrificed on the same day and kids.
About 200 18-month old llamas were also sacrificed with the children.
Along with the children's remains, archaeologists uncovered the bodies of one man and two women near the sacrificial site.
The site where the children and baby llamas were found has been under excavation since 2011, when the site first made headlines after the discovery of 42 children and 76 llamas during an emergency dig.
The pre-Columbian burial site, known as Las Llamas, contains the skeletons of 140 children who were between the ages of five and 14 when they were ritually sacrificed during a ceremony about 550 years ago, experts who led the excavation told The Associated Press on Friday. The skeletal remains of both the children and the animals show cuts to the sternum and rib dislocations. The researchers think the adults may have performed the ritual killings then were executed shortly after. The three adults found had blunt-force trauma to the head and no grave, leading scientist to believe they, too, were part of the sacrifice.
In the layers of sediment at the site, researchers found evidence that the region had experienced severe rainfall and flooding around the same time as the sacrifices, likely due to elevated sea temperatures from an El Niño event.
It's thought the ritual was a single event, which if confirmed would be the largest single mass child murder event known of in the world. "Maybe there was a need for a new type of sacrificial victim".
"Las Llamas is already such a unique site in the world, and it makes you wonder how many other sites like this there may be out there in the area for future research", Mr Prieto said. "They may have seen that [adult sacrifice] was ineffective".