Apo Reef is a series of coral reefs encompassing 34 square kilometers within the waters of Occidental Mindoro in the Philippines. It is the world's second-largest contiguous coral reef system and the largest in the country. The reef and its surrounding waters are administered as a National Park as part of the Apo Reef Natural Park project; the Apo Reef is within the Sulu Sea. Apo Reef can be found around 33 kilometers west off of the mid-western coast of the Philippine island of Mindoro. Two separate coral reefs make up the atoll-reef system. The two reefs are separated by a 30 meter-deep channel between them. Several environments can be found within the reef's boundaries. Aside from coral reefs, seagrass meadows, beds of macroalgae and mangrove stands are present on and around the reef proper. The waters of Apo Reef are protected within a National Park encompassing 274.69 km2 of the reef and its surrounding area. Of the total area, 157.92 km2 comprises the Apo Reef Natural Park while the remaining 116.77 km2 constitute a buffer zone surrounding the national park. Politically, the reef lies in waters within the jurisdiction of the province of Occidental Mindoro in region IV-B of the Philippines. It is directly administered by the local government of the municipality of Sablayan. Originally, Apo Reef was first officially declared a "Marine Park" by then-Philippine president Ferdinand Marcos in 1980. This was followed up with the local government of Sablayan declaring the reef a special "Tourism Zone and Marine Reserve" three years later. In 1996, the entire reef was declared a protected natural park by then-president Fidel Ramos. In 2006, the Protected Areas and Wildlife Bureau of the Philippine Department of Environment and Natural Resources submitted the reef to the UNESCO World Heritage Centre for consideration as a World Heritage Site.