English: It was described by Strabo (629-30) as an orifice in a ridge of the hillside, in front of which was a fenced enclosure filled with thick mist immediately fatal to any who entered except the eunuchs of Kybele. The Plutoneion was mentioned and described later by numerous ancient writers, in particular Dio Cassius (68.27), who observed that an auditorium had been erected around it, and Damascius ap. Photius (Bibl. 344f), who recorded a visit by a certain doctor Asclepiodotus about A.D. 500; he mentioned the hot stream inside the cavern and located it under the Temple of Apollo. There is, in fact, immediately below the sidewall of the temple in a shelf of the hillside, a roofed chamber 3 m square, at the back of which is a deep cleft in the rock filled with a fast-flowing stream of hot water heavily charged with a sharp-smelling gas. In front is a paved court, from which the gas emerges in several places through cracks in the floor. The mist mentioned by Strabo is not observable now. The gas was kept out of the temple itself by allowing it to escape through gaps left between the blocks of the sidewalls.