In today’s society, human sacrifice is not legal, and considered cruel and barbarian. But in ancient cultures, both animal and human sacrifices were normal and even necessary to please the gods. If we analyze the ritual of sacrifice of the oldest cultures, we can see that there are considerable variations. For example, the Greek practice both animal and human sacrifices, but not so often; while in the other hand, the Aztecs practiced mainly human sacrifices and very often.

The Greeks have a long tradition for sacrifices: "We see in Greece a society in which the basic ritual acts in daily practice are of a sacrificial type. For nearly ten centuries, guided by immutable cultic statutes, the Greeks never failed to maintain relations with the divine power through the highly ritualized killing of animal victim, whose flesh was consumed collectively according to precise strictures" (Detienne and Vernant 1).

"the general principle seems to have been that the victims should be edible food for men; and Suidas mentions as the regular ones sheep, swine, goats, fowls and guse" (Rouse 298).

Sacrifices had various purposes that were even social or political like the wedding ceremony or the ratification of an alliance pact between cities.

Another common situation when sacrificed was used was after marriage. "We know that sacrifices where customary before marriage, and where there is sacrifice there may always be votive offerings. Human sacrifices were also quite popular but seldom represented in art. Slavesand prisoners were the victim sof choice among the Greek population.

The Aztecs indulged mainly in human sacrifices. The Aztecs believe that since man was created by the sacrifice of the gods, he must reciprocate by offering them his own blood in sacrifice. If man could not exist except through the creative force of the gods, the gods in turn needed man to sustain them with human sacrifice. Man must nourish the gods with the magic sustenance of life itself, found in human blood and in human hearts. "If through the sacrifice of the gods the existence and motion of the sun is made possible, only through the sacrifice of the man would the present age be preserved. The ‘People of the sun’ undertook for themselves the mission of furnishing it with the vital energy found in the precious liquid that keeps man alive. Sacrifice, and ceremonial welfare to obtain victims for the sacrificial rites, were their central activities, the very core of their personal, social, military, and national life."(Leon-Portilla 28).

Many of their sacrifices were dedicated to specific gods. The sacrifices to the goddess of earth involves a rite where the victim was flayed and the priest dressed in his skin; men were burned in the honor the god of fire. But the most popular were the sacrifices for the su, the supreme god. On a special day called Tezcatlipoca (“Movement" or "Earthquake") prisoners of war were sacrificed by the priests, who tore out their hearts and offered them to the sun. On that day all the people practiced the rite of self-sacrifice by pricking blood from their ears or from other parts of their bodies and observing a rigorous fast until midday?.

They also had the Toxcatl Festival, which was held in the fifth month . On the day of this festival a youth was slain who for an entire year previously had been carefully instructed in the role of victim. He was previously selected form the best war captives of the year. He assumed the name, and attributes of Tezcatlipoca himself, and during that year was treated a god. Later in the year he was mated to four beautiful maidens of high birth, who were supposed to do anything he want them to.

At last the fatal day upon which he must be sacrificed arrived. He took a tearful farewell of the maidens whom he had espoused, and was carried to the teocalli of sacrifice, upon the side of which he broke the musical instruments with which he had beguiled the time of his captivity. When he reached the summit he was received by the high-priest, who speedily made him one with the god whom he represented by tearing his heart out on the stone of sacrifice. Aztecs had also gladiatorial sacrifices involving a real duel between a prisoner captain and several of the most distinguished Aztec warriors.

In the Sacrifice of the Dancer or the Xalaquia, a female captive or slave danced a whole day until daybreak. Then,  the chiefs and headmen, along with the victim, danced the solemn death-dance. In the end, she was stripped to a nude condition, the priest plunged a knife of flint into her bosom, and tearing out the still palpitating heart, offered it up to Chicomecohualt. In this manner the venerable goddess, weary with the labor of inducing growth in the maize-plant, was supposed to be revivified and refresh.

In the Vedic culture, "the sacrifice is to such an extent the principle par excellence that one ascribes to it not only the origin of the man, but even that of the god"(Aguilar 18). In the Vedic culture, just as in the Aztec culture, we see the principle that the world as well as humans were created from the sacrifice of a god. The sacrifice of man in the Vedic culture follows that of the gods, but it is not as widely practiced as in the Aztecs culture. Agni, the god of fire, was also called the sacrificer.