Simple Illustrated Guide to Greek Mythology
THE UNDERWORLD AND ITS MYTHS
The Underworld
In the Greek Mythology, all spirits after death went to the Underworld. But to go, a proper burial was needed. Also, a coin, or 'obola' would be placed under the tongue of the dead, since this fare was given to the boatsman, Charon, in order to cross the river Acheron, to reach the underworld. It was said that Artemis and Apollos was partook in shooting arrows at the men and women who died a natural death, and various others Gods caused other deaths. Hermes had the role of transporter of  souls, or Pyschopompus to the Underworld.
There were a few entrances to the underworld. one in Taenarum, in southern Greece, anothe rin Sicily. The "shadows" ashe soul of the death were called, were conducted through this entrances down to the banks of the River Acheron in the underworld, where they were met by an elderly man rowu=ing a boat, Charon. Charon would inspect for the obolos was present, the shadow had to wait on the shore for one hundred years, before being ferried crossed.
On the other shore lay the Gate to the Underworld, guarded by the three headed dog , Cerberus , who would keep all shadows from returning to the upper world. They were met the three infernal judges, Minos, Rhadamanthys, and Aeacus, who determined the souls ultimate destination in the Underworld, of which were three possibilities.
1) Plain of Asphodeal
2) Elysium Fields
3) Tartarus
Most of the dead were sent to the 'Plain of Asphodel', a dreary place where souls went about the same activities they pursued in the Upper World, in a slow mechanical fashion.
A small number of the souls who were heroic  in some way were sent to the "Island of the Blest", or "Elysium Fields. Here were the poets, brave soldiers, priests, living in care free existence, perpetually happy, living a blissful life.
At the bottom of the Underworld were sent the wicked and dammed, an area called Tartarus, a place of eternal darkness. Here, the dammed were tortured. Amongst the inhabitants were Sisyphus, the Danaids, Tityus, Ixion, Salmoneus, Tantalus, the Titans, The Hundred-Handed Giants, Otus and Ephialtes, Phlegyas, and Ocnus. They all had done especially sinful acts, usually against the Gods.
Ruling over the Underworld was Hades and his wife, Persephone. They were usually surrounded by a retinue, which include the Furies, Hecate , and various  other spirits. Near their throne  was the Chairs of Forgetfulness, which, if one was unlucky enough to sit ther one would stay ther forever, as did Pirithous in his quest for the hand of Persephone (See myth of Theseus).
From the foot of the thrones of Hades and Persephone flowed the rivers which channelled the Lower Lord:
1) Cocytus, rolling salt waves, composed of  nothing but the  tears flowing contunually from the eyes of the criminals condemned to hard labour in Tartarus
2) Phlegethon, a river of fire
3) Acheron, a black and deep stream to be passed by all souls were they reached  Hades' throne  and heard his decree; the current of this stream was so sift that even the boldest swimmer could not pass over; Charon ferried the souls across with the only available boat
4) Stix: by whose waters the gods swore their most irrevocable oaths, and whose waters transmitted invulnerability, as ocuured when the Thetis dipped her son, Achilles, into the river by his heels. Since his heels did not make a contact with the water they were vulnerable.
5) Lethe, whose waters had hte power to make one forget all unplesant things, thus preparing the good for a state of endless bliss in the Elysian Fields.
The Danaids
The Danaids were so named because they were 50 daughters of King Daneus, who resided in Egipt, near his brother, King Aegyptus (after whom the country is named) and has his 50 sons.
King Aegyptus proposed a mass marriage between families, but King Daneus, fearing treachery, fled with his 50 daughters  to the Greek isle of Argos . But Aegyptus was persistent, following his brother and his children to Argos.
Finally, Dameus appeared to agree to the arrangement. But secretly, he equipped all his daughters with daggers, to kill their husbands on their wedding night. All except one, Hypermestra, did so. Hypermestra did not, because she had been spared her virginity. To punish such henious act, the Danaids were forever condemned to Tartarus. Their duty consisted of having to fetch  water from the river, with jars full of holes, a task of unending futility.
Sisyphus
A well-know myth. Sisyphus was the son of the King of the Winds, Aelous. He caught sight of Zeus, carrying off a river-nymph, Aegina. Aeginas' father, Aesopus, searched for her, asking Sisyphus' help. Sisyphus revealed the identity of Zeus to Asopus. For his betrayal, Zeus sentenced Sisyphus to Tartarus, where he had to ask of rolling a huge stone up a hill, always to roll back just before reaching the top. Today, a 'Sisyphean task' denotes effort which is unceasing, never reaching the goal intended.
Salmoneus
One thing the Olympian Gods could not tolerate was a mortal having the arrogance to imitate them. This act was done by Salmoneus, brother of Sisyphus, who, as King of Ellis, drove his chariot, throwing torches to imitate the thunderbolts of Zeus, and dragging metals behind the chariot to imitate thunder.
For this act , Zeus condemned Salmoneus to the underworld, in the section of Tartarus. In biology, a genus of bacteria, Salmonella, which causes typhoid fever, is named after this king.
Tityus
Tityus, influenced by jealous Hera, attempted to rape Leto, mother of Artemis and Apollo, and affair of Zeus'. For this impious act, Zeus sent Tityus, a Giant, to Tartarus, where he was bound hand and foot, to have vultures eternally feed on his liver, a punishment similar to that suffered by Prometheus, in the Caucasus, in Asia Minor.
Ixion
King of hessaly, north of Greece, Ixion intended to marry a princess, for whom he was to apay a dowry. However, he lured his future father-in-law to a hidden pit of burning coals, into which he fell and died. Ixion travelled the lands , attempting to be purified of such a crime , but no-one would do it. Zeus, feeling sorry for Ixion, invited him to Olympus to be purified. But Ixion tried to seduce Zeus' wife Hera, who told Zeus of such attempt. To test Ixion, Zeus fashion a cloud , resembling Hera, with which Ixion coupled, producing , incidentally, the Centaurs. Zeus sentenced Ixion to Tartarus, tied to a fiery, spinning wheel , revolving continuously.
Otus and Ephialtes
Twin giants, they fell in love with the two Olympian goddesses Hera and Artemis. They attempted to assault Mt. Olympus to abduct the goddesses. But Artemis influenced a deer run between them, and the Giants each threw a spear at the interposed deer, missing the target, but killing each other. In Tartarus , they were tied to a column with live snakes, back to back.
Tantalus
Son of Zeus and the Titaness Pluto, Tantalus ruled the country of Lydia, a man of great wealth, and arrogance. He invited the Olympian Gods to dine with him, and to test the Gods' divinity,, he cooked his own son, Pelops, in a stew, serving it to the Gods. He is said also to have stolen ambrosia and nectar from Mt. Olympus.
For these severe transgressions , Tantalus was sent to Tartarus, to suffer continual thrist and hunger . he was placed in a pool, neck-deep. Everytime he attempted to drink the water, it would recede. Fruits trees hung above him. Everytime he tried to pluck the fruit, wind will blow the branches away from his grasp. In addition, a great stone hung above his head, held by a thread, causing him to live in constant fear. The English word "tantalize" is derived from his myth, meaning to tease by exposing to view, but keeping out of reach something much desired.
Phlegyas
Son of Ares and Chryse, Phlegyas was King of the Lapithae in Thessaly, father of Ixion. The Olympian, Apollo, violated Phlegyas went to Delphi, and burned the sacred temple of Apollo there.
For this sacrilegious act, Phlegyas was sent to Tartarus, tried to wall, with a large stone at the edge of a cliff above, forever keeping Phlegyas in terror.
The Giants and The Titans
As discussed in Chapter 2, Zeus condemened the Titans to Tartarus, after he overthrew them and Cronus, his father. The Giants were also sent to Tartarus to guard the Titans, so they would not cause more trouble for Mt. Olympus.
Ocnus
Ocnus' punishment in Tartarus was somewhat comical. He was doomed to knit a rope of straw, which was continuously eaten by a donkey as it was being made. In the Upper World, Ocnus had been married to an extravagant wife, who continuously spent his money after he earned it. It was thought that Ocnus, in a fit of anger, murdered his wife, prompting his punishment in Tartarus of endless knitting of rope, a task, like many others in Tartarus,of ceaseless frustation.