South Africa's economic hub Johannesburg was born from a gold rush in the 19th century. Today, the illegal mining of gold and other minerals is threatening its infrastructure - damaging the city's transport and power networks, as well as homes and buildings.

South Africa’s economic hub Johannesburg was born from a gold rush in the 19th century. Today, the illegal mining of gold and other minerals is threatening its infrastructure - damaging the city’s transport and power networks, as well as homes and buildings.