Indian Union Territory Andaman and Nicobar Islands has 836 islands, but only 31 are occupied. A 150 km (93 mi) wide waterway separates the two main groups of islands: the northern Andaman Islands and the southern Nicobar Islands. Port Blair (officially Sri Vijaya Puram), the territory's capital and biggest city, is about 1,190 km (740 mi) from Chennai and 1,255 km (780 mi) from Kolkata in mainland India. The islands are between the Andaman Sea and the Bay of Bengal. At 901 km (560 mi), the northernmost point is farthest from where the Hooghly River starts. Located at 6°45'10"N and 93°49'36"E on the southern tip of Great Nicobar, Indira Point is the southernmost point of India. With Indonesia to the south (about 103 mi), Myanmar to the northeast (280 km), and Thailand to the southeast (650 km), the region shares ocean borders. With a total land size of about 8,249 km2 (3,185 sq mi), the islands are home to 380,581 people, according to the 2011 census. Nicobar, South Andaman, North and Middle Andaman, and Car Nicobar represent the three districts, with Port Blair, Mayabunder, and Nicobar serving as the cities. According to genetic and culture research, the native Andamanese people may have been cut off from other groups during the Middle Palaeolithic period, which happened more than 30,000 years ago. Civilisation has been traced back 2,200 years using archaeological data. Cholas, one of the three Tamil countries, used the islands as a naval base to send missions to Southeast Asia in the 11th century CE. Denmark was the first country in Europe to reach the islands in 1755. Starting in 1868, the islands were a part of the British Raj. During World War II, the Japanese Empire attacked the islands. Following India's independence in 1947, the area was made a province, and after the Constitution of India was passed in 1950, it became a union state. The islands are home to the Andaman and Nicobar Command, which is the only regional command that is run by the Army, the Air Force, and the Navy simultaneously. Although Hindi and English are the official languages, Bengali, Tamil, and Telugu are the most common languages spoken. Some native speakers speak languages in the Andamanese or Nicobarese family. The main faith in the union territory is Hinduism, but there is a large Christian minority. Additionally, the islands are home to the Sentinelese people, a tribe that has never been met.