Aztec burial of a sacrificed child at Tlatelolco. The exact ideologies behind child sacrifice in different pre-Columbian cultures are unknown but it is often thought to have been performed in order to placate certain gods.
The Aztecs believed that, if sacrifices were not given to Tlaloc (a rain god), the rain would not come and their crops would not grow. Archaeologists have found the remains of 42 children sacrificed to Tlaloc. In every case, the 42 children, mostly males aged around six, were suffering from serious cavities, abscesses or bone infections that would have been painful enough to make them cry continually. Tlaloc required the tears of the young so their tears would wet the earth. As a result, if children did not cry, the priests would sometimes tear off the children’s nails before the ritual sacrifice. (Source)