Sub-Saharan Africas greatest and at over 2500sq kilometres (900sq miles) the world's largest inland city, Johannesburg straddles rows of jagged quartzite ridges, beneath which a century of gold mining has produced a veritable honeycomb of tunnels. Technology may have claimed the mine sands but millions of trees have risen from the sprawling suburbs on satellite images, much of Johannesburg resembles a rainforest an unexpected backdrop to a formidable array of Victorian and Edwardian architecture, as well as concrete, chrome and glass skyscrapers. Makeshift shacks of scrap, reflected in the glossy glass faade of the old Johannesburg Stock Exchange building on Diagonal Street, bear testimony to the chasm between the fantastically wealthy and the desperately poor that still divides this city.

Situated 550km (344 miles) from the nearest port, on a vast inland plateau, 1700m (5700ft) high, Johannesburgs climate is much milder and drier than its latitude would suggest and is also free of malaria, a disease that plagues much of the rest of Africa.