Ancient Origins has a new article up with the brilliant title: 'How Ancient Greeks took Trippy journeys to the land of the dead'. In short, the article is about the Nekromanteion (Νεκρομαντεῖον) --the ‘Oracle of Death’--which was an ancient Hellenic temple in Epirus in which supplicants sought to consult shades of the dead.

The Nekromanteion is made up of a twisting labyrinthine passageway and subterranean chambers. The dimensions of the Chamber of the Dead show it was constructed using advanced knowledge of acoustics. The sound effects facilitated the impression of communicating with the dead. The late Greek archaeologist Sotirios Dakaris found a large amount of broad beans at the site when he excavated it in the 1950s and ’60s. These beans are known for their hallucinogenic properties when eaten in their green state. They can also cause giddiness. Similar effects are caused by lupine seeds, which were also found at the site. Sensory manipulation through acoustics, choreographed movement, darkness, and hallucinogens likely made this a genuinely ethereal experience for such supplicants.

Caves had a special place in ancient Hellenic worship, and were often devoted to the ancient Gods, such as Zeus, Apollo, and Cybele and particularly to Pan and the Nymphs. They were dark places full of votive offerings and altars, which would come to life during rituals attended by the ancient followers of the Gods. Caves in the ancient Hellenic religion often connect to the wild and unknowable: not only do they often house 'monsters' (like the Cyclops in the Odysseia, and the Centaur Kheiron), but they are the houses of 'wild' women like Calypso, as well as of the Nymphs, and Pan. Yet, these are not completely wild; they occupy the space between the untamed wild and the carefully tended field of civilized life.

Divination is attested to cave worship more often. In Minoan times, caves were places one visited to go on a type of vision-quest ritual, whereby the worshipper went into a trance to encounter a deity. In the later Hellenic periods, this type of ritual use seems to have faded, but divination still played a large part in the ritualized function of caves. Oracular forms of knowledge were inspired by Apollo and the Muses, and they often came from the bottom of a cave, like at Delphi. There are many other testaments to caves where visitors flocked to the receive prophetic dreams, oracular messages or other divine messages.

Besides an oracular function, caves were also sometimes considered entrances to the Underworld--indeed, the Underworld itself, located under the surface of the Earth, is an immense cave. At Eleusis is a shallow cave, the Cave of Hades, or as it was known then, the Precinct of Plouton. The would be initiates of the Mysteries would have visited this cave as part of their preparation. Most likely, there were sacrifices made here, and perhaps rites of purification. The cave was considered the exact place where Kore was abducted, and for the initiates, it would have been a place to of death, from which only the purified would return to 'live again', like Persephone.

The Nekromanteion seems to have had a touch of all these elements incorporated into it, making it a mystical and sacred place unlike many others. The temple of necromancy was devoted to Hades and Persephone. This site was believed by devotees to be the door to Hades, the realm of the dead. The site is at the meeting point of the Acheron, Pyriphlegethon and Cocytus rivers, believed to flow through and water the kingdom of Hades. Although other ancient temples such as the Temple of Poseidon in Taenaron as well as those in Argolis, Cumae, and Herakleia in Pontos are known to have housed oracles of the dead, the Necromanteion of Ephyra was the most important.

Ritual use of the Necromanteion involved elaborate ceremonies wherein celebrants seeking to speak to the dead would start by gathering and consuming a meal of broad beans, pork, barley bread, oysters, and a narcotic compound. Then followed a cleansing ceremony and the sacrifice of a sheep. The faithful would then descend through a series of corridors leaving offerings as they passed through a number of iron gates. The nekyomanteia would pose a series of questions and chant prayers and the celebrants would then witness the priest arise from the floor and begin to fly about the temple through the use of Aeorema-like theatrical cranes. Undoubtedly oracular message were either spoken or recieved directly to and by the participants.

The Necromanteion functioned until 167 BC when it was looted and destroyed by the Romans, but it had a very long run in which it functioned as a religious site; it was first mentioned by Hómēros in the 8th century BC.