Johannesburg is the most populated city in South Africa, it rises up on a plateau. Johannesburg has got the biggest airport in Africa, the O.R. Tambo International. The airport is linked to the city centre by train, bus and motorway. Johannesburg is an important destination, in fact it is connected to the main worldwide destinations by the main international airlines. The travel length is approximately 12 hours. The national company is South African Airways, but there operates also Emirates and British Airways.