Zeus had decided to destroy humankind. A pouring rain from the heavens flooded the world, so that all men were destroyed, except Deucalion and his wife Pyrrha. They had been forewarned of the deluge and built an ark. Some sources suggest that Deucalion is to be identified with Aquarius, the water bearer. The rains of the water bearer are a gift from the gods.
Deucalion and Pyrrha drifted to the high mountains, where an oracle told them to "throw the bones of their mother" behind them. They decided that their mother is Gaia and stones are her bones. They threw rocks behind their shoulders, and the rocks formed people and repopulated the Earth. Those thrown by Pyrrha became women; Deucalion's became men.
Deucalion