A chapel on a rocky hill near the Acheron and the site of Lake Acheroussía marks the location of the Nekromanteion, a sanctuary dedicated to Hades and Persephone at the entrance to the Underworld where the Ancients came to consult the spirits of the Dead through the oracle. The traces of the building that are now visible are Hellenistic (3C BC), but the Nekromanteion was already in existence in the Mycenaean period (1550-1100 BC). It comprised a series of corridors and rooms culminating in the sanctuary itself.