Mary New Eve
It is based on and reaffirms the fact that Jesus is the New Adam, come to undo the Fall of the first Adam. Early Christians taught that the Annunciation marks the reversal of the temptation of the first Eve. In the Garden, Eve believed the lies of a fallen angel, disobeyed God and so became the cause of Adam's Fall (Genesis 3:1-7). At the Annunciation, Mary believed the words spoken by a holy angel, obeyed God and so became the Mother of the One who would save us from Adam's Fall! Mary's obedience reversed Eve's disobedience; thus Mary is the New Eve for the new creation in Christ.
Just as Eve cooperated with Adam in the Fall, Mary cooperates with Jesus. St. Elizabeth's inspired reference to Christ as the "fruit of (Mary's) womb" (Luke 1:42) also identifies Our Lady as the New Eve. The first Eve gave Adam the forbidden fruit, and so she became the indirect cause of the Fall, The New Eve gave the New Adam "the Fruit of her womb" - His human Body, in which He suffered and died for us - and so she became the indirect cause of the Redemption. St. John's depiction of Calvary clearly parallels the Garden of Eden: there is a tree (the Cross - see Galatians 3:13), a man (Jesus) and a woman (Mary).