the country's third city, was founded in 1557 on the rigorous planning guidelines issued 30 years earlier by the Spanish king Charles V. One of the region's agricultural and administrative centres, it has been a melting pot for local and immigrant populations. Cuenca's architecture, much of which dates from the 18th century, was 'modernized' in the economic prosperity of the 19th century as the city became a major exporter of quinine, straw hats and other products. Cuenca is located in the highlands of Ecuador at about 2,560 metres (8,400 feet) above sea level, with an urban population of approximately 400,000 and 700,000 inhabitants in the larger metropolitan area. The center of the city is listed as a UNESCO World Heritage Site due to its many historical buildings.