The Aztecs did many things to keep the gods happy. These things included human sacrifices. They believed this helped keep the world from ending. The Aztecs believed that the gods had created them, and that human sacrifice was the most powerful way of giving back the gift of life. The Aztecs also believed that the gods were in an almost never-ending struggle. The hearts and blood from the sacrifice fed the good gods to give them strength to fight the evil gods. The human sacrifices often took place on the Templo Mayor, the Aztecs' great pyramid temple. 