Patmos, an Aegean island in the north of Greece’s Dodecanese island group, is a significant Christian pilgrimage site. Its Cave of the Apocalypse is where John of Patmos (St. John the Theologian) is said to have written the Book of Revelations. A fortress-like, an 11th-century monastery dedicated to the saint overlooks the whitewashed houses of the hilltop capital, Hora (also known as Chora).