The Cave of the Apocalypse on the Island of Patmos is located to the north and below The Monastery of Saint John. The Cave of the Apocalypse marks the traditional site where it is said that John received the revelation from Jesus and dictated it to his disciple, Prochorus. The Cave is inside the Chapel of Saint Anne, and unfortunately they do not allow picture taking inside the Church or the Cave.
For a map locating Patmos and Introductory Commentary Click Here.