Luanda: the most expensive city?
But how does the city like that officially inhabited by 4,7 million (http://en.wikipedia.org/wiki/Luanda) look like?
Just a quick scan on google maps: a small CBD patch surrounded by endless slum-like patterns which in some places get into kind of a grid shape.
Definitely, housing in a city that has suffered decades of civil war is an issue. One of the recent projects Kilamba Kiaxi for your judgement: