http://en.wikipedia.org/wiki/Kingdom_of_Aksum
http://en.wikipedia.org/wiki/Kanem_Empire
http://en.wikipedia.org/wiki/Ghana_Empire
http://en.wikipedia.org/wiki/Mali_Empire
Africa had big and influential civilizations, but in the end they were destroyed by colonization and slave trade. For nobel laureates: today most blacks are educational disadvantaged. Would have african nations colonized europe it would be the other way.
Additionally, just to tease these racists: it is well known that humans all are coming from africa. This is founded on genetical analysis. So the genetical divergence in blacks is a lot bigger than in any other ethnic groups. This is, because humans developed in Africa and only a few of them (with a smaller gene pool between them) left Africa and settled in the rest of the world. So mostly every gene in other ethnic groups gene pool is existant in the black gene pool. In a way you could construct from that, that blacks are superior to other humans. 
For the ones claim we all look that different: Sexual selection works wonder for changing visible features in a few generations, but it usually has no effect on genes with no visible effects.
http://en.wikipedia.org/wiki/Sexual_Selection







