The Ilissos River is a historic river located in Athens, Greece. It was once a significant waterway in ancient times, flowing through the city and providing water for its inhabitants. The river is associated with various myths and was often mentioned by ancient writers, including Plato. Today, the Ilissos River is mostly underground, with parts of it having been covered by urban development. Despite this, its historical importance remains, and efforts have been made to preserve its legacy. The river's banks were once a popular gathering place for Athenians, contributing to the cultural life of ancient Athens.