Japanese Occupation, the military general headquarters of the Commonwealth Army of the Philippines remained active from January 3, 1942, to June 30, 1946, and the 5th Constabulary Regiment of the Philippine Constabulary was established from October 28, 1944, to June 30, 1946, and stationed in Albay. Then came the clearing operations and anti-Japanese insurgency in the Bicol Peninsula, helped by the local Bicolano resistance. Some Bicolano guerrilla groups invaded around the province of Albay during the Japanese Insurgencies between 1942 and 1944 and were supported by local Filipino troops under the Philippine Commonwealth Army and pre-war Philippine Constabulary 5th Infantry Regiments attacking the enemy soldiers of the Japanese Imperial Army. In the aftermath of three years of siege and conflicts, many Bicolano guerrillas were forced to retreat by the Japanese around the province before liberation in 1945 by Allied forces. Geography Albay has a total land area of , which makes it the 53rd biggest province. The province is bordered by the provinces of Camarines Sur to the north and Sorsogon to the south. To the northeast lies the Lagonoy Gulf, which separates the province from Catanduanes. To the southwest of the province is the Burias Pass with the island of Burias of Masbate province located about offshore. In 2016, an area of was declared a UNESCO Biosphere Reserve. The Albay Biosphere Reserve is home to 182 terrestrial plant species, of which 46 are endemic to the Philippines. Its marine waters and coastal area also provide habitat to five of the world's seven marine turtle species, as well as mangrove, seagrass and seaweed ecosystems. Topography The province is generally mountainous with scattered fertile plains and valleys. On the eastern part of the province is a line of volcanic mountains starting with the northernmost Malinao in Tiwi, followed by Mount Masaraga and the free-standing Mayon Volcano. Separated by the Poliqui Bay is the Pocdol Mountains in the town of Manito. The stratovolcano of Mayon standing at around , is the highest point of the province. It is the most famous landform in Albay and in the whole Bicol Region. This active volcano falls under the jurisdiction of eight municipalities and cities of Albay: Camalig, Daraga, Guinobatan, Legazpi City, Ligao City, Malilipot, Santo Domingo, and Tabaco City. The western coast of the province is mountainous but not as prominent as the eastern range with the highest elevation at around . Among these