A coffin that has been broken into by vandals sits in the graveyard in the ex-nitrate mine of Puelma. Hundreds of abandoned ex-nitrate mines are scattered across the Atacama desert, the driest place in the world. The mine of Chacabuco was also used as a concentration camp by Pinochet in the early 1970's. When Germans invented a synthetic nitrate in the early 1900's the 'white gold' being mined in the Atacama soon became worthless and whole towns were abandoned. When they were functioning the workers worked like slaves being paid with fichas, or plastic chips, that could only be exchanged for goods in the shops located in the mines.