The three rivers that separate the Underworld from the world of the living are: Phlegethon, Lethe, and Styx.
According to the Greek Mythology, the Underworld was considered to have been surrounded by five rivers:
Acheron (river of woe)
Cocytus (river of lamentation)
Phlegethon (river of fire)
Styx (river of unbreakable oath by which the gods took vows)
Lethe (river of forgetfulness)
Upon death, a soul was led by Hermes near the entrance of the underworld, where the ferry awaited to carry it across the Acheron. There was a single ferry run by Charon, the boatman who took the souls across the river. Only those who could pay the fare with coins placed on their lips when buried, were granted passage; the rest were trapped between two worlds. After the boat ride, the souls entered through the gates; Cerberus allowed everyone to enter, but none to leave. The souls then appeared before a panel of three judges, Rhadamanthus, Minos, and Aeacus, who passed sentence based on their deeds during their previous life. The souls who were good went to the Elysian Fields, while the others were singled out for special treatment.
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