Lima was originally founded as Ciudad de los Reyes (City of Kings) by the Spanish conquistador Francisco Pizarro on January 18th, 1535. As the capital of the Viceroyalty of Peru it was the most important city in South America during the colonial period, especially during the 17th and early 18th centuries. A massive earthquake in 1746 destroyed much of the city and also the neighbouring port of Callao, leading to a decline in the city's fortunes. Modern Lima is the capital of Peru and a sprawling metropolis covering approx 800 km² / 310 sq miles with a population of around 10 million. It has grown dramatically since the middle of the 20th century due to migration from rural areas; around a third of Peru's population live here and it is one of the largest cities in South America. Situated in Peru's coastal desert region on the Pacific coast, it is a fascinatingly diverse and vibrant city.