Bartolome, a desolate island with few plants is the most visited and most photographed island in the Galapagos. The island consists of an extinct volcano and a variety of red, orange, green, and glistening black volcanic formations. The best known of the island's features is the Tuff Cone known as Pinnacle Rock. This large black partially eroded lava formation was created when magma expelled from the volcano reached the sea. When the seawaters cooled the hot lava it caused an explosion. The exploded particles eventually fasten together forming a rock composed of thin layers. Bartolome's Pinnacle Rock has become one of the best recognized and most photographed sights in the islands. A prominent sight it was used as a target for US airmen during WWII. Lying beside the Pinnacle Rock are twin half moon shaped beaches. The northern beach is a popular snorkeling site where visitors have the opportunity to swim with fish, Sea Lions and Galapgos Penguins. Much larger animals can be found near the southern beach including stingrays, spotted eagle rays, white-tipped sharks, and black-tipped sharks.