Why are Whites so much more intelligent than Blacks?

Name me a single majority Black country that is 1st world. The most developed parts of the world are North & Western Europe, North America, Australia & New Zealand, and East Asia. Most of those places are White countries. Everywhere else in the world is a run-down cesspool of disease and violence, the worst being Black countries. Even in places where there was NO slavery, Blacks make their ghetto nests and spread crime while begging for handouts and blaming Whitey. The US is similar to the UK in the fact that, Blacks are only a small minority, yet commit nearly half the crime (13% of the US population is Black, but they commit 49% of all crimes). Why can't we just ship them to Liberia? Think of how much time and tax money will be saved on welfare, medical care for STDs, prisons, education, property damage, political correctness, etc. We won't have to dumb down our education system because there will be no Blacks to drag down the other children while crying "racism".