Prometheus was a Titan, son of Iapetus, whose name means "he who thinks ahead", the far-sighted one. His brother Epimetheus, "he who thinks afterwards", was careless. In the war against the Titans Prometheus sided with Zeus, but his great love was for humans.
Creating humans
In one tradition it was Prometheus who shaped the first humans from clay and water in the image of the gods, while Athena breathed life into them. Epimetheus, tasked with handing out qualities to living creatures, gave animals claws, fur, wings and speed, and when he reached humans he had nothing left: man was naked and defenceless.
The theft of fire
To help humans, Prometheus tricked Zeus during a sacrifice, getting him to choose the worse part of an ox: bones wrapped in fat, while the meat went to mortals. In anger, Zeus took fire away from them. So Prometheus climbed Olympus, stole a spark from the Sun's chariot or Hephaestus's forge, hid it in a hollow fennel stalk and brought it to earth. With fire humans learned to cook, keep warm and work metals: civilisation had begun.
The punishment
Zeus had Hephaestus chain Prometheus to a cliff in the Caucasus. Every day an eagle ate his liver, which grew back each night. The torment lasted for ages, until Heracles shot the eagle and freed the Titan. The tragedy Prometheus Bound, attributed to Aeschylus, tells of his proud defiance.
Pandora and the jar
To punish humans too, Zeus ordered Hephaestus to make the first woman, Pandora, "she who has all gifts": each god gave her a quality, beauty, grace, skill, but also curiosity. Zeus sent her as a bride to Epimetheus, who welcomed her despite his brother's warnings. Pandora brought a jar (in Hesiod a large pithos, later called a "box") that must not be opened. Driven by curiosity, she opened it: out flew all the evils of the world, toil, sickness, old age, death. Pandora managed to close it in time to keep only hope at the bottom.
The flood
Prometheus's son Deucalion and Pandora's daughter Pyrrha were the only survivors when Zeus sent a flood to punish wicked humanity: they built an ark and landed on Mount Parnassus. To repopulate the earth, the oracle told them to throw "the bones of the great mother" over their shoulders: they understood these were the stones of the Earth. From the stones Deucalion threw came men, from Pyrrha's came women.
See also the Titans, the origin of the world and myths and words.