Island of Rebirth

North of the Island of Flame, off the shores of Avelorn, lies the Island of Rebirth, site of the Earth Mother's shrine. Here, in the depths of the beautiful Gaen valley, lies the cavern-temple of the Mother Goddess, where the Everqueen is crowned. Herein dwell the priestesses of Isha, an oracular order whose origins lie shrouded in the mists of time. Within the underground complex, many mysterious rites take place which no male Elf is allowed to witness. Every female Elf is expected to make a pilgrimage here at least once in her life.

Source

 * Warhammer Armies: High Elves (8th Edition) -- pg. 11