There are Five rivers according to Greek Mythology: Acheron (woe), Cocytus (wailing), Phlegethon (fire), Lethe (forgetfulness), Styx (across with which spirits of the dead were ferried also the river of dreams lost because of death)
The River Styx is the most well known river in the Underworld. It is the river of oath. Charon has to ferry the dead souls across it so they can enter the Underworld. The river Lethe is also an...