As the fourth-largest land mass on Earth with a total of 400 million people and 17,843,000 square kilometers, the large subcontinent of South America is surrounded by the Atlantic and Pacific oceans. Highlands, river basins and mountains form the different characteristic landscapes of the continent; among its various states are Brazil, Ecuador, Chile, Bolivia and Peru. The world's largest river, the Amazon extends with a length of 6,448 km over the entire continent.