Check out a full version of the story by our buddy, Thomas Bulfinch:
Zeus, in his anger, resolved to destroy the human race by burying it beneath the waves of a deluge. But once again Prometheus was on guard. He warned his son Deucalion who, with his wife Pyrrha, daughter of Epimetheus and Pandora, then reigned in Thessaly. On the advice of his father, Deucalion constructed an ark and with his wife went aboard. For nine days and nine nights they floated on the waters. On the tenth day the downpour ceased and the two survivors disembarked on the crest of Mount Othrys or Mount Parnassus. Deucalion offered up sacrifice to Zeus Phyxius (protector of fugitives) and the god, touched by his piety, promised to grant him his first wish. Deucalion asked Zeus to renew the human race.
Another legend says that Deucalion and Pyrrha, having gone to Delphi, addressed their prayers to Themis. 'Veil your heads,' replied the goddess, 'remove the girdles of your robes and cast behind you the bones of your first ancestor.' Stricken at first with astonishment, Deucalion and Pyrrha at last solved the mystery of this ambiguous command.
They veiled their heads and walked across the plain, throwing over their shoulders stones torn from the earth—for were they not descendants of Gaea, the earth, and were not the rocks her very bones? The stones which Deucalion threw were changed into men, those that Pyrrha cast were transformed into women.
The human race was renewed and Zeus recovered from his anger. Deucalion was regarded as the father of the Hellenes, the first king and founder of towns and temples. It was he, they said, who built the temple of Olympian Zeus at Athens, and nearby the temple his tomb was pointed out. In Cynos, however, they also boasted of having the tomb of Deucalion and his wife Pyrrha.