Cordillera Central (Luzon) Sierra Madre Mountains, the longest mountain range in the country, through the Caraballo Mountains in Nueva Vizcaya province. During Spanish colonial period, the whole range was called "Nueva Provincia", (New Province). The Cordillera Central is the highest mountain range in the Philippines. It comprises about 1/6 of the whole Luzon island with a total area of . The highest mountain in the range, Mount Pulag, is also the highest mountain on Luzon Island at . It is officially the third highest mountain in the country after Mount Dulang-dulang and Mount Apo on Mindanao Island, the second largest island of the
Apo Reef facilities are available onshore to protect the island's fragile ecosystem. Apo Menor is located near the western end of Apo Reef, about east of Apo Island. It is a rocky limestone island with relatively little vegetation. Cayos del Bajo are flat coralline rock formations with no vegetation on the northern lagoon near the eastern edge of the reef. At low tide, many small rocks are dry on the reef, particularly along its north side. The main activity of the reef relates to its underwater quality. Scuba diving and snorkeling in Apo Reef area are exceptional due to the quality of