Sandton's claim rests on what it contains. This is the home of the Johannesburg Stock Exchange, the largest in Africa and among the dozen largest in the world, which relocated here from the inner city in 2000 and pulled the centre of financial gravity with it. Roughly a tenth of all companies listed on the JSE keep their offices within the district. Major banks, multinationals, and the local headquarters of foreign firms cluster along Rivonia Road and Sandton Drive, packed into a Central Business District that grew dense and vertical in record time. The land itself was assembled in the late 1960s out of Sandhurst farmland, never zoned for a city, never planned to become one, and yet it did. A handful of developers bought up roughly 32 hectares of estates and horse paddocks, and within a generation the paddocks had given way to one of the densest concentrations of capital on the continent.

At the heart of the district sits Nelson Mandela Square, presided over by a six-metre bronze statue of the man himself, arms slightly open, watching over the crowds below. The square adjoins Sandton City, which together with it forms one of the largest shopping complexes in Africa, some 144,000 square metres of retail. The pairing is a study in South African contrasts: a monument to the country's most revered freedom fighter standing guard over a temple of luxury consumption. Tourists pose at Mandela's feet; shoppers stream past with bags from international brands. The square is where the new South Africa most plainly meets the old hierarchies of wealth it was meant to dismantle.

Sandton was built for the car, and the car exacts its price. The arteries that feed it, the M1, the N1, Rivonia Road, William Nicol Drive, choke twice a day as the district's workers pour in and out, and the rush-hour crawl between roughly 7 and 9 in the morning and 4 and 7 in the evening is a local rite of endurance. Relief arrived with the Gautrain, a sleek, secure commuter rail line that links Sandton to central Johannesburg, to Pretoria, and directly to OR Tambo International Airport. It is faster and pricier than the older MetroRail network, but it gave the square mile something it had always lacked: a way in that did not involve sitting in traffic.

If Sandton is where Johannesburg makes its money, it is also where the city does its most expensive entertaining. The Saxon, one of the finest hotels in the country, is where Nelson Mandela stayed shortly after his release from prison and where he worked on his memoir, Long Walk to Freedom. Around it spread the splurge hotels, the fine-dining rooms, and the convention centres that host the deals and the diplomacy. Just to the west, older neighbourhoods like Melville offer a grittier, more bohemian counterpoint, with street vendors selling their own art and a culture that never priced itself out. But Sandton sets the tone: this is the address South Africa's wealth chose for itself, glittering, guarded, and entirely self-made.