The mummified corpse of a child lies exposed in the Puelma Cemetery. This was where miners living in Chacabuco, a 19th Century nitrate mine settlement, were interred. At the time 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. In recent times people have dug up the corpses in search of jewellery and even skulls. While, in the 1970s General Pinochet's regime used the miner's dwellings as a concentration camp.