A retreat for Orthodox pilgrims and publicity-shy celebrities, Patmos owes its mystical aura to the 11th-century Monastery of St. John, which dominates the UNESCO-protected settlement of Chora. Follow wafts of incense into the mosaic-paved courtyard, where black-robed monks go about their devotions. Marvel at the religious icons, Byzantine frescoes, and embroidered vestments glimmering in the chapels. The library is a trove of rare manuscripts and books, including a 6th-century copy of St. Mark's Gospel written in gold and silver script on purple vellum. A short walk downhill is the crepuscular Cave of the Apocalypse, where St. John wrote the Book of Revelations. Light a candle and pray that the end of the world isn’t nigh.