Mona Island is an ecological reserve off the west coast of Puerto Rico, noteworthy for its wildlife, white beaches, and unspoiled limestone caves. The island, about 7 square miles in area, was formed several million years ago when plate tectonics forced it out of the surrounding ocean. On the northern end of the island, the cave open up onto sheer cliffs 200 feet above the ocean. El Faro was one of the major cave systems on Mona Island, and that is where I took most of the cave photos. El Faro was one of the major cave systems on Mona Island, and that is where I took most of the cave photos. These caves were created by a combination of ocean and wind. Buy my travel book!