The role of human sacrifices in the major civilizations of Meso and South America was mainly RELIGIOUS.
The person that was killed, was given as a present to please some God or spirit. Human sacrifice was common within the Incan and Aztec culture for example.
The Inca also practiced child sacrifice, and some of their mummies have been found at the top of mountains and volcanos.
The Maya practiced human sacrifices only on special occasions and generally at their temple.
