Argentina is a country located in the southern half of South America. It is the second-largest country in South America after Brazil, the fourth-largest in the Americas, and the eighth-largest in the world. Argentina is bordered by Chile to the west and south, Bolivia and Paraguay to the north, Brazil and Uruguay to the northeast, and the South Atlantic Ocean to the east. Its capital and largest city is Buenos Aires, situated along the eastern coast near the Río de la Plata estuary. The country spans diverse geographical regions, including the Andes mountains to the west, the Pampas grasslands in the center, and the Patagonia region in the south.