Eleusis — Sanctuary of Demeter

For nearly 2,000 years — from approximately 1500 BCE to 396 CE — the town of Eleusis hosted the Eleusinian Mysteries, initiatory ceremonies held in honour of Demeter and Persephone. The Mysteries were the single most important religious institution of the ancient Greek world; initiates included Plato, Cicero, Marcus Aurelius, and reportedly most educated Greeks and Romans of the classical period.

Initiates were bound by oath of death never to reveal what they witnessed in the Telesterion (initiation hall). Despite centuries of participation, the content of the final rite remains unknown. Scholars including the classicist Walter Burkert and ethnobotanist R. Gordon Wasson have proposed that the ritual drink kykeon contained ergot-derived psychoactive compounds, inducing a transformative visionary experience. The sanctuary was destroyed by Alaric's Visigoth army in 396 CE, ending the tradition.