Capital of Africa

If one city is to be called the "Capital of Africa", what would it be?  Here are the candidates:

1.  Nairobi, Keyna.  The United Nations has its regional headquarters there and the UN and other international agencies contribute more than $350 million to the Kenyan economy.  English is an official language (along with Swahili).

2. Addis Ababa, Ethiopia.  Often referred to as the "political capital of Africa".  The headquarters of the African Union is there, along with the United Nations Economic Commission for Africa (UNECA).

3. Midrand, South Africa (suburb of Johannesburg).  Seat of the Pan-African Parliament and of the NEPAD Secretariat (an economic development program).

4.  Cairo, Egypt.  With almost 15 million people in its metropolitan area, it is the largest city in Africa, and the largest in the Arab-speaking world.  Negatives: it is too tied to Egypt and the Arab-speaking world, and being a big city has its negatives - overcrowding and pollution.

5. Abuja, Nigeria.  Planned city which is the capital of Nigeria as well as the Economic Community of West  African States (ECOWAS).  The site of the Abuja Treaty, which created the African Economic Community, with the goal of a single currency.  Probably the future headquarters of the African Central Bank.

6. Port Louis, Mauritius.  This is a tiny island country 1,200 miles off the coast of Africa, but one of the most economically free countries on earth and has a high Human Development Index (HDI).  It is called the "Switzerland of Africa".  It serves as the headquarters for Chinese investment in Africa.

7. Arusha, Tanzania.  The "judicial capital" of Africa.  Home of the International Criminal Tribunal for Rwanda.  One of the branches of the Mechanism for International Criminal Tribunals (the other branch is in The Hague, Netherlands).  Future home of the African Court of Justice.  Also the headquarters of the East African Community (EAC).

8. Cape Town, South Africa.  The best place in Africa for a business conference.  The seat of the South African National Parliament.  A center for information technology, and home of the University of Cape Town, probably the top university in Africa.

9. Gaborone, Botswana.  Planned city which is the capital of Botswana.  Also has the headquarters of the South African Development Community, which consists of 14 states.

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I think it should be in Johannesburg, whether in Midrand or elsewhere in the area. This is because Johannesburg is the financial capital.  It is the home of the largest stock exchange in Africa and the Rand is the strongest currency.