Johannesburg, the commercial capital of South Africa, is home to far more dollar millionaires than any other city in Africa, research has found.
The "city of gold" topped the continent's rich list with 23,400 millionaires at the end of 2012, according to New World Wealth, a consultancy based in Oxford in the UK. It is followed by Cairo in Egypt with 12,300 millionaires and Lagos in Nigeria with 9,800.
Johannesburg became the economic engine of Africa after the discovery of gold in 1886, rapidly transforming from a settlement of tents and wood and iron shacks to a modern metropolis. It claims to be the world's biggest city not built on or near a major water source, and to host the world's biggest urban artificial forest.
Despite one of the slowest economic growth rates in Africa, South Africa has four cities in the dollar millionaires top 10. Cape Town, a darling of tourists, is in fourth place with 9,000, Durban is sixth with 2,700 and Pretoria eighth with 2,500.
The highest-ranking city in east Africa is Nairobi, the Kenyan capital, in fifth place with 5,000. Casablanca in Morocco is seventh with 2,700. Luanda, the capital of Angola, often said to be most expensive city in the world in which to live, is ninth with 2,400. The top 10 is completed by Algiers in Algeria with 2,300.
Wealthy South Africans include Johann Rupert, the luxury goods tycoon, Nicky Oppenheimer, of the diamond mining dynasty, and Patrice Motsepe, the country's sole black billionaire, who this year donated half his fortune to charity. Africa's richest man is the Nigerian cement entrepreneur Aliko Dangote, with a personal fortune estimated at $11.2bn (£7.2bn).
In the top 10 country rankings, South Africa comes out on top with 48,800 millionaires, followed by Egypt with 23,000 and Nigeria with 15,900.
New World Wealth's report said Accra in Ghana was expected to be the fastest-growing major city for African millionaires, with the number rising from 800 in 2012 to 1,500 in 2020.
Ethiopia and the Ivory Coast are expected to be the fastest-growing African markets for millionaires, with growth of 7.4% a year to 2020. Zambia, Ghana and Angola are also expected to grow strongly.
"Millionaire" refers to individuals with net assets of $1m or more excluding their primary residences.
The millionaires boom offers little consolation to Africans at the bottom of the heap: South Africa remains one of the most unequal societies in the world. Professor Mthuli Ncube, chief economist at the African Development Bank, said the "Africa rising" narrative was intact, but added: "Some of it has been jobless growth, frankly, and the idea now is it must create jobs.
"The good thing now is that the leadership is recognising this, whether it's political or economic. They see that the quality of the growth needs to be improved and we see the opportunity with natural resources as one way to do it. Structural transformation is critical for the attainment of inclusive growth."
