Lima is the capital and the largest city of Peru. It is located in the valleys of the Chillón, Rímac and Lurín rivers, in the central coastal part of the country, overlooking the Pacific Ocean. Together with the seaport of Callao, it forms a contiguous urban area known as the Lima Metropolitan Area. With a population of almost 10 million, Lima is the most populous metropolitan area of Peru, and the third largest city in the Americas (as defined by "city proper"), just behind São Paulo and Mexico City.