A little background before we jump into the big man's trials and tribulations. Hercules (or Herakles if you're Greek), was the son of Zeus, conceived in one of Zeus's infidelities. This pissed off Zeus's wife Hera and she spent a lot of effort to make Herakles's life miserable. But her nastiest deed was to make Herakles mad for a day (some say she got him drunk) and cause him to kill his wife and children. When he came out of his madness, Herakles was heartbroken. He went to the oracle at Delphi and she told him to indenture himself to King Eurytheus for twelve years. The famous Labors are the result of this servitude.
Here they are in order:
Labor 1 - Kill the Nemean Lion; Easier said than done since this particular lion had a hide that was impervious to sword or spear. Hercules (let's go with this name since its more familiar) beat the lion to death with his club and skinned him - I know, how did he do this since the hide was invulnerable? For the rest of his life Hercules wore the skin to make himself invulnerable.
Labor 2 - Kill the Lernean Hydra - This monster was a dragon who, if you cut off one head grew two. For this labor, Hercules brought along his nephew - I'm not kidding. As soon as Hercules cut off a head, nephew cauterized the wound, preventing new heads from growing.
Labor 3 - Capture the Ceryneian Hind - The beast had bronze hooves and golden horns. Hercules had to be careful not to hurt the creature since it was sacred to the god Artemis. I do believe by this time Hercules was somewhat pissed at King Eurytheus because when the creature did take some hurt, Hercules said it was the king's fault.
Labor 4 - Capture the Erymanthian Boar - This creature had been terrorizing King Eurytheus's kingdom and had slaughtered many of the king's greatest warriors. Hercules netted the beast and brought it straight away to the king, who was so frightened by the boar's appearance he hid in a large vase.
Labor 5 - Clean the Augean Stables - These stables belonged to Augeus another son of a god, this time Helios, the sun. These putrid stables housed hundreds if not thousands of horses and had not been cleaned for years. Hercules diverted a river into the stables and Viola, spic and span.
Labor 6 - Kill the Stymphalian Birds - Even though these bad, bad birds tended to kill everyone who had the misfortune to stray into their forest (they had beaks and claws made of iron and a taste for human flesh), they must have heard of the prowess of Hercules because they hid out in the upper branches of their trees and refused to come down to play. The Goddess Athene, who obviously favored Hercules over Hera, gave Hercules a set of golden castanets that drove the birds mad and forced them into the light of day. Hercules then shot them one by one with his bow and arrows.
Labor 7 - Capture the Bull of Minos - Yes indeed, the same Minos of Crete that harbored the dread Minotaur. But wait, it gets better. This particular legendary white bull was the sire of the Minotaur (with Queen Pasiphae who when she saw how beautiful the bull was had to have a little bovine love). Poseidon had ordered this bull sacrificed and the current king of Minos had refused. Thus Hercules's labor. After capturing the bull, the famed hero Theseus found it and fulfilled Poseidon's wish. The Bull was sacrificed on the fields of Marathon.
Labor 8 - Capture the Horses of Thrace - These particular horses, all mares by the way, were fond of human flesh. Their owner, King Diomedes, loved to feed unlucky wanderers to his string of ponies. Hercules killed the evil king, fed his body to the mares, and while the horses were sated captured them.
Labor 9 - Steal the Girdle of Hippolyte, Queen of the Amazons - A renowned warrior, Hippolyte did battle with Hercules. The girdle which had magical powers, made her even more lethal but in the end Hercules killed her. I think this particular Labor was a nasty bit of business.
Labor 10 - Bring Back the Cattle of Geryon - Geryon was a monster (three bodies, if you can wrap your head around that) in the company of a giant named Eurytion and a massive two-headed Hell Hound (Orthus). These three nightmares together guarded an immense herd of wild red-furred cattle on the plains of Hesperides (pretty much Spain) Hercules did battle with all three and killed them all. He then had do a cattle drive from Spain back to Greece.
Labor 11 - Steal the Apples of Hesperides - Yes the same Hesperides of the 10th Labor. The golden apples were guarded by a a giant serpent named Ladon. To make matters worse Hera herself had owned the apples. They were a wedding present from the Goddess Gaia when she married Zeus. As if Hera didn't already have enough reasons to be pissed at Hercules. Since Hera had her eye on Hercules, he used subterfuge and convinced the Titan Atlas that he would take over his burden of holding up the Earth if Atlas would pick the apples. Rumor has it that not only did Atlas pick the apples but on his way back he freed his brother Titan from the eternal torture Zeus had laid on him. Oh and course, he returned and gave the apples to Hercules.
Labor 12- Descend into Hades and Capture the famed Three-Headed Dog Cerberus - For this one, Hercules need the help of two gods - Hermes and Athene. But they could only get him into the underworld; he would need the cooperation of Hades himself. The dark god agreed that Hercules could take the dog if he could best him without weapons. Hercules wrestled the beast and defeated it. Oh yeah, in his spare time, Hercules found and released Theseus who Hades had imprisoned.
After all this you would think Hera would be super angry with the god-hero but in the end, hero and goddess reconciled. On his death, Hercules ascended onto Olympus as a god where he married Hera's daughter Hebe.
All's well that ends well.