Calama is a city in the Atacama Desert in northern Chile. It is the capital of El Loa Province, part of the Antofagasta Region. Calama is one of the driest cities in the world with average annual precipitation of just 5 mm (0.2 inches)[citation needed]. The River Loa, Chile's longest, flows through the city. Calama has a population of 143,000 (2005 census). At an elevation of 2,400 metres (7,900 feet), Calama is the gateway to the geological and archaeological wonders of Chile’s high central desert. Some of these places of interest include: the town of Chuquicamata, the village of San Pedro de Atacama, Valle de la Luna (Valley of the Moon), the Licancabur volcano, R. P. Gustavo Le Paige Archaeological Museum, Los Flamencos National Reserve, the Aguas Calientes salt flat, the Tuyajto lagoon, the El Tatio Geysers, the village of Chiu-Chiu. In 2003 the nearby town of Chuquicamata, by one of the largest open-pit copper mines in the world, was dismantled, partly because of environmental reasons, and partly due to encroachment from the mine's expansion. Residents of Chuquicamata then moved to Calama, away from company-owned residences, to find housing on their own.