Human Sacrifice

In the Aztec culture human sacrifice was an aspect of the culture for each of the eighteen festivities. This was a normal practice for the mesoamerican and south american cultures. In the Aztec "Legend of the Five Suns", all the gods sacrificed themselves so that mankind could live. Besides just human sacrifice animals and objects were also sacrificed so the Gods would be happy. There are also certain sacrifices that certain god's required to keep them happy and make the people that made the sacrifice go to the after life.

http://en.wikipedia.org/wiki/Human_sacrifice_in_Aztec_culture