The north of Chile stands out for the huge expanse of endless space, the subtle range of colours of the desert earth, the unique vistas of the highlands and natural phenomena such as the El Tatio geysers, fumaroles which are to be found in the middle of the Andes mountain range. Other places which offer spectacular scenery, wildlife and flora are the Isluga National Park, the Surire salt flat and the Lauca National Park with its traditional villages such as Putre and Parinacota. The northern zone is witness to the golden age of saltpeter and some former settlements which were built during this era, such as Humberstone and Santa Laura have been declared World Heritage Sites by UNESCO. As well as places like San Pedro de Atacama and the Elqui Valley, known for their alternative lifest<x>yles and "special" energy, there are modern cities like Iquique, Antofagasta and La Serena. Other highlights include Chuquicamata, the largest open cast copper mine in the world and observatories such as Mamalluca and Cerro Tololo high in the Andes.