This ceremony, called “Capac cocha” in Quechua, consisted of the fact that once a year, at harvest time, each village sent the most beautiful and intelligent children on pilgrimage to Cusco, the capital of the Incas. Once there they were “blessed “and had to return to their homes, and the ones who managed to get till there, were sacrificed in a great ritual.
They were buried alive after sleeping them, together with their best clothes and a trousseau made up of jewels, utensils, food and miniature human and animal figures representing actions of everyday life.
In ancient Inca culture, children were considered purer than adults, and therefore more suitable for sacrifice, which was not considered as a punishment, rather the opposite, as an honor for the sacrificed, since after the Sacrifices were revered for a long time, almost as if they were gods.
That one and many more Inca traditions we learned about at the MAAM Museum in Salta, highly recommended!
In the museum we could see one of the three mummies that were found in the volcano Llullaillaco, the bodies remained almost in perfect condition due to the climatic conditions, the height and the cold.
Here I leave a link from Wikipedia in case you are interested in the subject.