With a population of more than 20 millions Lagos is not only the biggest city in Nigeria, but also the biggest in Africa (though exact numbers don't exist). Though it's the economic hub of Nigeria, Abuja is the capital. It's obviously very big and spread out. It doesn't have a traditional city centre, but is more split into neighbourhoods. The islands (Victoria Island and Lagos Island) are the posh part of town, where Ikoyi is the most affluent neighborhood with a lot of embassies. Ikeja, near the airport, is an orderly commercial center, where the markets have some bustle. Of course there are slums and crazy congested neighborhoods, but they have little appeal for most travelers, maybe except for Makoko stilt village, which can be seen from the expressway at the 3rd Mainland Bridge.