In 1678, a Chaldean priest from Baghdad reached the Imperial Villa of Potosí, the world’s richest silver-mining camp and at the time the world’s highest city at more than 4,000 metres (13,100 feet) above sea level. A regional capital in the heart of the Bolivian Andes, Potosí remains – more than three and a half centuries later – a mining city today. Its baroque church towers stand watch as ore trucks rumble into town, hauling zinc and lead ores for export to Asia. Elias al-Mûsili – or Don Elias of Mosul, as he was known – arrived in 17th-century Potosí...