The Alfeios river is famous in the Greek mythology. It was one of Heracles tasks to clean the Augean Stables. Heracles succeeded by rerouting the rivers Alpheus and Peneus to wash out the filth. With its 110 km, the Alfeios River is the longest river in the Peloponnese. Its source is near Megalopoli in the prefecture Arcadia. It flows along Olympia and empties into the Ionian Sea in the prefecture of Ilia, near Pyrgos.