Zeus favored his son so much that Hera became jealous. She became so jealous that she had tried to kill Hercules by putting two deadly snakes in his crib to poison him and eat his flesh. Although, when the snakes were put in the crib, Hercules, instead of being poisoned and eaten, found the snakes amusing and played with them as though they were mere rattles. Hercules ended up killing them instead of them killing him.
Hercules ended up in the mortal world and was raised by a poor, old mortal couple. When he had grown up he found a happy life with his wife Megara and had two children.
In the Roman version of Hercules' story, even after he'd grown up and many years had passed, his mother's jealousy remained. She drove Hercules mad and tricked him into thinking that his family was his enemies, thus resulting in him killing them. So he went to his cousin, Eurthsesus, (who Hera had tricked Zeus into crowning king instead of Hercules) to ask for Twelve Tasks to regain his honor.
In the Greek version, when Hercules found out that his parents were gods, he asked to become a god as well, so he would be able join them on Mt. Olympus. His mother gave him the Twelve Tasks that would make him a hero, which would be enough to make him a god.The Twelve Tasks
The First Task: Defeat of the Nemean Lion.

Hercules knew that this would not be an easy task. He'd heard that the lion had skin that could not be pierced by arrow or spear. So his plan was to go to it's cave and bash it in the head with his club, but when he tried, his club broke in half.
It was then it became clear the only option was to defeat the monster in hand-to-hand combat. Hercules eventually won by strangling the Nemean lion. He then took its skin as a token of victory and wore it as a cloak.

The Second Task: Destroy the Learnean Hyrda.

The next opponent was the many-headed monster called the Hydra. Some said it had three heads and some said it had nine. No one could agree on exactly how many heads it really had. Its breath was so deadly that even the smell of its footprint was enough to kill any mortal being, but Hercules, being half god, did not die.
So Hercules tracked down and found the monster and attempted to cut off one of it's heads only to find that two more sprouted back in place of the one he had just cut off. The long snake-like heads then coiled themselves around his body.
He then remembered his nephew, Idous, who had driven him to the place of the hydra. At first his nephew tried not to heed his uncles cries, but eventually gave up and ran over to help. They then became a team and while Hercules cut the head and Idous seared the wounds before more heads grew back.
When there was only one head left, which was supposedly immortal Hercules trapped the monster inside a cave and barricaded it with a bolder.

The Third Task: Capture of the Ceryhean Hind

The Ceryhean Hind was a swift doe with horns of gold that was sacred to the goddess of the hunt, Artemis. Hercules knew that Artemis would not be happy if he had killed the animal so he had to somehow bring it back alive. Hercules tracked it down for almost a year before he captured it. He caught it taking a drink from the stream and shot an arrow between its bone and tendons on both of its legs pinning to the ground.Although the deer had not been killed, Artemis was still displeased with Hercules. He barely dodged her wrath by blaming it on his taskmaster and cousin.

The Fourth Task: Capture the Erymanthian Boar

Upon trying to track down the boar, Hercules visited a centaur named Pholus. As Pholus examined an arrow that was poisoned with the hydra's blood, he accidentally dropped the point onto his foot and he died.
Hercules then, sadly went back to his hunt for the boar. After a few days he found it on Mt. Erymanthian and managed to drive it into a huge snow bath, making it impossible for it to move. Hercules then took it over his shoulder and carried it back to his taskmaster.

The Fifth Task: To clean the Augoan Stables

Eurysthemus then decided to choose a task to humiliate his cousin. He then told Hercules to clean the Augean Stables in one day. Also, he wasn't allowed to use any man made tools. Hercules then used two rivers and diverted their coarse to run through the stables and wash them clean.

The Sixth Task: Get Rid of the Stympalian Birds

The Stymphalion were birds that lived in a marsh near lake Stympalian. Nobody knew whether they killed the humans with their brass feathers and ate the flesh or they were just a nuisance.When Hercules got there he realized there would be only one way he could get close to them in a marsh. So he then began to make a lot of racket to scare them into the sky and shot them down with his arrows.

The Seventh Task: Capture of the Cretan Bull

The Queen of Cretan, Queen Pasiphate had been cursed to fall in love with a bull by a vengeful god, and as a result the Minotaur was born; a monster half human and half bull that snorted flames which haunted the Labyrinth of Cretan and ravaging around the countryside.
The Minotaur put up a good fight, but was eventually caught and shipped to the mainland.

The Eighth Task: Capture the Mares of Diomedes

The mares of Diomades were horses that ate the human flesh of travelers who accepted their hospitality. In one version of the story of the eighth task, Hercules pacified them by feeding them their master.
In another version he pacified them by giving them his squire, Adberus. After Hercules caught them he sent them to Eurestheus, who released them to be eaten by the wild animals on Mt. Olympus.

The Ninth Task: Retrieve Hippolyte's Belt

Next was to retrieve the Queen of the Amazon, Hippolyte's belt. The Amazons were a tribe of proud warrior women. Hercules brought some other heroes with him to help, thinking that the amazons would put up a fight.
Instead Hippolyte willingly gave it to him, but Hera wasn't about to let him finish the task so easily. She spread a rumor through the Amazon tribe that Hercules had kidnapped their Queen and then chaos started. Hercules ran for it with the belt.

The Tenth Task: Stealing the Cattle of Geryon

Geryon was the proud owner of the famous cattle in Spain. These cattle either had three heads and/or three separate bodies, but it wasn't just a simple matter of herding a bunch of cattle. Geryon also had a watched dog called, Orthrus, a dog with two heads that snapped at our hero.The dog was killed with one strike with Hercules' club and he also dispatched Geryon making his path clear. Although Hercules took a wrong turn and went through Italy before coming back to Greece, he still made it.

The Eleventh Task: Retrieving the Apples of the Hesperides

The Hesperides were nymphs that guarded the special apples that were given to Hera as a wedding gift. The apples were kept behind a high wall and also guarded by a many-headed dragon called the Ladon.
The apples were located on the western mountains that were named for Atlas, who had sided with his brother in the war against Zeus. As a punishment he was to hold up the burden of heaven upon his shoulders for eternity. Hercules was told that he could not complete his task without the aid of Atlas.
Atlas was only too happy to help. He made a deal with Hercules, Hercules was to first slay the Ladon and then to hold up the pillar of Heaven while Atlas retrieved the apples for him. So Hercules shot the Ladon with an arrow over the high wall and took the pillar. Atlas returned with the apples, but realized how nice it was not to have the strain of the heavens on his back.Hercules then tricked Atlas into taking the pillar by asking Atlas if he could hold the pillar up just long enough to let him fetch a cushion for his shoulder. Hercules then got away.

The Twelfth Task: Capture of the Cerberus

The Cerberus was the hellhound that guarded the gates of the underworld. The only way to the to the underworld was to cross the famous Styx, river of the underworld, but to do that he would have to make Charon let him cross, who had certain conditions for letting people cross. One, you had to be dead, or two, you had to hold a coin under your tongue; Hercules had neither.As he thought, the Charon would not let him cross, but Hercules glowered so fearlessly that the Charon eventually let him cross. Hercules then faced the Cerberus. It snapped it's razor sharp teeth on it's many, many heads, thrashed it's snake tail as a swarm of snake heads came from it's back to bite Hercules. They bit him, but he was wearing his lion skin so their teeth could not hurt him. Hercules then strangled the Cerberus.
Hercules dealt with many monsters and completed his tasks. His death came when he had come back home and gave his wife gave him a cloak soaked in the centaur's blood, which was supposed to keep him faithful. But the centaur was killed with an arrow that had blood from the hydra, which was now in the blood soaked cloak, so Hercules died in agony.