The Fall of Man
The Fall of Man is one of the most fundamental parts of Christian theology, the genesis of Original Sin and man's separation from God. While not specifically mentioned in the Old Testament, theologians have applied the term "the Fall of Man" to the events in Genesis 3, when Adam and Eve eat the fruit from the Tree of Knowledge of Good and Evil, and are subsequently banished from the Garden of Eden.
Catholic theology on the Fall of Man notes that this was a primeval event at the very dawn of history, when this first sin was transmitted from Adam and Eve to all human descendants. Catholics maintain that baptism is required to wash away the stain of original sin, the justification for infant baptism. Eastern Orthodox churches, in contrast, teach that the Fall of Man did not result in passing down this original sin, but instead lead to the fallen condition of the world, of which man's sinful nature is a manifestation.
The notion of the Fall of Man can also be found in religions outside of Christianity. The Ancient Greeks believed that the original state of the world was a type of Golden Age. After Prometheus stole fire from the gods, the gods gave Pandora a box, telling her not to open it. They knew of course, that her curiosity would drive her to open the box, which released evil into the world. Thus the Fall of Man is perhaps a metaphor for the presence of death and destruction in the world.