Argentina, officially the Argentine Republic (Spanish: República Argentina, pronounced [reˈpuβlika arxenˈtina]), is the second largest country in South America, constituted as a federation of 23 provinces and an autonomous city, Buenos Aires. It is the eighth-largest country in the world by land area and the largest among Spanish-speaking nations, though Mexico, Colombia and Spain are more populous. Argentina's continental area is between the Andes mountain range in the west and the Atlantic Ocean in the east. It borders Paraguay and Bolivia to the north, Brazil and Uruguay to the northeast, and Chile to the west and south. Argentine claims over Antarctica, overlapping claims made by Chile and the United Kingdom, are suspended by the Antarctic Treaty of 1961. Argentina also claims the Falkland Islands (Spanish: Islas Malvinas) and South Georgia and the South Sandwich Islands, which are administered by the United Kingdom as British Overseas Territories. Argentina is a founding member of both the United Nations and the Union of South American Nations. Argentina is one of the G-20 major economies.