Demeter's most significant cult center was Eleusis, a town near Athens where the Eleusinian Mysteries were celebrated annually for well over a thousand years, from roughly the seventh century BCE until the sanctuary was closed and destroyed in late antiquity, making it one of the longest continuously practiced religious rites in the ancient Mediterranean. Unlike most Greek civic religion, which was public and open, the Mysteries required initiation, and initiates swore never to reveal what they witnessed inside the sanctuary's great hall, the Telesterion, an oath so effectively kept that modern scholarship still cannot reconstruct the precise content of the central rite with certainty, only its surrounding structure of purification, procession from Athens along the Sacred Way, fasting, and a culminating nighttime revelation. What ancient sources agree on is the promise made to initiates: a better fate in the afterlife than the vague, joyless existence Greek belief generally assigned the dead, a promise tied directly to Persephone's own yearly return from the underworld. The Mysteries admitted a strikingly broad range of participants for the ancient world, including women and even slaves, provided they spoke Greek and had not committed murder, a scope that made Eleusis one of the most widely shared religious experiences in the whole Greek speaking world.