Chile's Region III de Atacama (area 75,176 km2 (29,026 sq miles) covers the southern part of the Atacama Desert, its capital is Copiapó. It is one of the least populated Regions in Chile; many people migrated to the area during a mining boom in the second half of the 19th century and mining is still the main industry. The desolate Puna de Atacama (shared with Argentina) in the east of the Region is home to several of the highest peaks in South America, including Nevado Ojos del Salado (6893m / 22,615 ft, the highest volcano in the world and 2nd highest peak in the Andes) on the border near Paso San Francisco. Most of the mountains in this high altitude desert border region are of volcanic origin. The following separate galleries are also located in Region III: Nevado de Tres Cruces National Park, Llanos de Challe National Park.