The Cave of the Apocalypse is situated about halfway up the mountain on the Aegean island of Patmos, along the road between the villages of Chora and Skala.
This grotto is believed to mark the spot where John of Patmos received his visions that he recorded in the Book of the Apocalypse (Revelation).
In 1999, UNESCO declared the cave a joint World Heritage Site together with the Monastery of Saint John the Theologian.
Source: wikipedia.org