Ploutonion
A ploutonion (Ancient Greek: Πλουτώνιον, lit. "Place of Pluto") or plutonium (from the Latin) is a sanctuary specially dedicated to the ancient Greek and Roman god Pluto. Only a few such shrines are known from classical sources, usually at locations that produce poisonous emissions and were considered to represent an entrance to the underworld.
At Eleusis, the ploutonion was near the north entrance to the sacred district (temenos). It was built by Peisistratos in the 6th century BC and rebuilt two centuries later, when the Eleusinian mysteries were at the height of their influence. The cave was the traditional site of the birth of the Divine Child Ploutos.
The Greek geographer Strabo mentioned three sites as having a ploutonion. One was on a hill between Tralleis and Nysa. Its precinct encompassed a sacred grove, a temple of Plouton and Persephone, and an adjoining cave called the Charonion, after the ferryman of the dead. According to Strabo, it "possesses some singular physical properties" and served as a shrine for healing and a dream oracle (incubation).
