Bahrain, officially the Kingdom of Bahrain, is a sovereign state in the Persian Gulf. The island nation comprises a small archipelago made up of 33 natural islands and an additional 51 artificial islands, centered around Bahrain Island which makes up around 83 percent of the country's landmass. The country is situated between the Qatar peninsula and the north eastern coast of Saudi Arabia, to which it is connected by the 25-kilometre (16 mi) King Fahd Causeway. According to the 2010 census, Bahrain's population is over 1.2 million, of which around half are non-nationals. At 780 square kilometres (300 sq mi) in size, it is the third-smallest nation in Asia. The capital and largest city is Manama. Bahrain is the site of the ancient Dilmun civilization. It has been famed since antiquity for its pearl fisheries, which were considered the best in the world into the 19th century. Formerly an emirate, Bahrain was declared an Islamic constitutional monarchy in 2002.