Located on the broad alluvial fan of the Rimac River, Lima is the capital of Peru and the only megacity (7.7 million inhabitants in 2002) located on the western coastline of South America. The city was established by Francisco Pizarro in 1535 and became an important colonial port, linking silver mines of the Altiplano of the high Andes Mountains with the burgeoning Spanish empire. During the mid-20th century, significant numbers of people relocated from rural mountain communities into the Lima metropolitan area. Problems now facing the metropolitan region include developing adequate water resources, controlling pollution, and preparing for natural hazards such as earthquakes and landslides.