Peeling walls of the ruins of the 19th Century nitrate mine settlement of Chacabuco. Once there was a worldwide demand for the nitrates found in abundance in the Atacama Desert. Chile used to be one its main exporters until German scientist Fritz Haber invented synthetic nitrate and put Chile's mines out of business. More sinisterly, in the 1970s General Pinochet's regime used the miner's dwellings as a concentration camp.