South America is a continent in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. It may also be considered a subcontinent of the Americas, or America, which is how it is viewed in Spanish and Portuguese-speaking regions of the Americas. The reference to South America instead of other regions has increased in the last decades due to changing geopolitical dynamics .It is bordered on the west by the Pacific Ocean and on the north and east by the Atlantic Ocean; North America and the Caribbean Sea lie to the northwest. It includes twelve sovereign states: Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Guyana, Paraguay, Peru, Suriname, Uruguay, Venezuela, and a part of France : French Guiana. In addition, the ABC islands of the Kingdom of the Netherlands, the Falkland Islands , Trinidad and Tobago, and Panama may also be considered part of South America. South America has an area of 17,840,000 square kilometers . Its population as of 2018 has been estimated at more than 423 million. South America ranks fourth in area and fifth in population . Brazil is by far the most populous South American country, with more than half of the continent's population, followed by Colombia, Argentina, Venezuela and Peru. In recent decades Brazil has also concentrated half of the region's GDP and has become a first regional power.Most of the population lives near the continent's western or eastern coasts while the interior and the far south are sparsely populated. The geography of western South America is dominated by the Andes mountains; in contrast, the eastern part contains both highland regions and vast lowlands where rivers such as the Amazon, Orinoco, and Paraná flow. Most of the continent lies in the tropics. The continent's cultural and ethnic outlook has its origin with the interaction of indigenous peoples with European conquerors and immigrants and, more locally, with African slaves. Given a long history of colonialism, the overwhelming majority of South Americans speak Portuguese or Spanish, and societies and states reflect Western traditions.