Few believed it. Rumors aside, most scholars assumed it was the conqueror Hernan Cordez and Spain rationalizing their genocidal colonization of Latin America. No peoples are that brutal.
But in 2015 and again in 2018, archeologists in Templo Mayor discovered more and more evidence to substantiate the old Spanish reports. It was true. The Aztecs, who controlled most of what would become Mexico, had been removing the beating hearts of perhaps 10,000 live victims every year and eating their bodies to appease their very demanding sun god.
It's not easy finding that many bodies, so wars had to be fought often. Sometimes daily. The Aztecs were very selective about whom they chose. Prime targets were physically attractive, strong and courageous. The gods demanded it. And it did not matter whether the sacrifice was a man, a woman or even a child; the sun god wanted them all.
Public gatherings would be held. Victims would be held down while the priest would take a sharp stone, slice open the chest and pull out the beating heart. Then the head would be sliced off.
The heart. The brain. The eye. Whatever looked particularly tasty would be eaten by the priest. Then, one of the individuals who contributed the most to the Aztec community would be given the rest of the body parts to share with his friends and family, or to just eat it himself if so inclined. To be given a headless, heartless corpse was quite the honor.
It gets worse. The sun god didn't want little children - but the rain god did. In particular, he wanted their tears. Lots of tears would be reciprocated with lots of rain for the crops. Most victims were males, around the age of six. Rather than go into detail describing mutilation of innocent children, let's just say that they were forced to cry for several hours. Imagine the worst and you will be on the right track.
Despite the brutality of these practices, all victims were honored with Paradise. Only three forms of death guaranteed entry to Bliss - war, childbirth and sacrifice to the gods. Most other tribes in the region believed the same. The dominant natives to the south of the Aztecs were the Mayans. They held athletic competitions in which the winners (not a typo) would be killed after the game was finished. Odd as it may seem, most contestants were Mayans who wanted the glory and the opportunity to get eaten by their own families.
When the Spanish arrived in 1519, Aztecs became the victims. Catholicism was imposed upon them. Most were forced into slavery. The Spanish navy lay siege and starved the natives by cutting off their food supply. By 1605, between the introduction of European diseases and mass slaughter, an estimated 24 million natives in New Spain (currently Mexico) would be killed.
In March of 2019, the president of Mexico sent letters to both the king of Spain and the pope, requesting an apology. He has yet to receive any reply.