Quito, formally San Francisco de Quito, is the capital city of Ecuador, and at an elevation of 9350 ft above sea level, it is the highest official capital city in the world and the one which is closest to the equator. It is located in the Guayllabamba river basin, on the eastern slopes of Pichincha, an active stratovolcano in the Andes mountains. With a population of 2,671,191 according to the last census (2014), Quito is the second most populous city in Ecuador, after Guayaquil. It is also the capital of the Pichincha province and the seat of the Metropolitan District of Quito. The canton recorded a population of 2,239,191 residents in the 2010 national census. In 2008, the city was designated as the headquarters of the Union of South American Nations.