Sarawak (/səˈrɑːwɒk/; Malay: [saˈrawaʔ]) is a state of Malaysia. The largest among the 13 states, with an area almost equal to that of Peninsular Malaysia, Sarawak is located in northwest Borneo Island, and is bordered by the Malaysian state of Sabah to the northeast, Kalimantan (the Indonesian portion of Borneo) to the south, and Brunei in the north. The capital city, Kuching, is the largest city in Sarawak, the economic centre of the state, and the seat of the Sarawak state government. Other cities and towns in Sarawak include Miri, Sibu, and Bintulu. As of the 2015 census, the population of Sarawak was 2,636,000. Sarawak has an equatorial climate with tropical rainforests and abundant animal and plant species. It has several prominent cave systems at Gunung Mulu National Park. Rajang River is the longest river in Malaysia; Bakun Dam, one of the largest dams in Southeast Asia, is located on one of its tributaries, the Balui River. Mount Murud is the highest point in Sarawak. The earliest known human settlement in Sarawak at the Niah Caves dates back 40,000 years. A series of Chinese ceramics dated from the 8th to 13th century AD was uncovered at the archaeological site of Santubong. The coastal regions of Sarawak came under the influence of the Bruneian Empire in the 16th century. In 1839, James Brooke, a British explorer, arrived in Sarawak. He, and his descendants, governed the state from 1841 to 1946. During World War II, it was occupied by the Japanese for three years. After the war, the last White Rajah, Charles Vyner Brooke, ceded Sarawak to Britain, and in 1946 it became a British Crown Colony. On 22 July 1963, Sarawak was granted self-government by the British and subsequently became one of the founding members of Malaysia, established on 16 September 1963. However, the federation was opposed by Indonesia leading to a three-year confrontation. The creation of Malaysia also prompted a communist insurgency that lasted until 1990. The head of state is the Governor, also known as the Yang di-Pertua Negeri, while the head of government is the Chief Minister. Sarawak is divided into administrative divisions and districts, governed by a system that is closely modelled on the Westminster parliamentary system and was the earliest state legislature system in Malaysia. Because of its natural resources, Sarawak specialises in the export of oil and gas, timber and oil palms, but also possesses strong manufacturing, energy and tourism sectors. It is ethnically, culturally, and linguistically diverse; major ethnic groups including Iban, Malay, Chinese, Melanau, Bidayuh and Orang Ulu. English and Malay are the two official languages of the state; there is no official religion.