Argentina, officially named the Argentine Republic, is a country located mostly in the southern half of South America. Sharing the bulk of the Southern Cone with Chile to the west, the country is also bordered by Bolivia and Paraguay to the north, Brazil to the northeast, Uruguay and the South Atlantic Ocean to the east, and the Drake Passage to the south. With a mainland area of 2,780,400 km², Argentina is the eighth-largest country in the world, the fourth largest in the Americas, and the largest Spanish-speaking nation. The sovereign state is subdivided into twenty-three provinces and one autonomous city, Buenos Aires, which is the federal capital of the nation as decided by Congress. The provinces and the capital have their own constitutions, but exist under a federal system. Argentina claims sovereignty over part of Antarctica, the Falkland Islands, and South Georgia and the South Sandwich Islands.