How African is North Africa?

The African Cup of Nations kicks off in Tunisia, with 16 nations taking part - and all eyes on the continent are looking north. Seen from space, Africa is one huge and undivided landmass. But for some on the continent, however, the widely-held perception is of two very different regions; Africa south of the Sahara desert, or sub-Saharan Africa, and north Africa. This article on the website of the BBC questions the nature of African identity and is followed by comments on the subject from around the world.