Okay this is boggling my mind.

Sub-Saharan Africans didn't really make it out of the stone age until Muslim and Europeans came to Africa.

Yet in Rhodesia, now Zimbabwe, this ancient town exists. Great Zimbabwe it's called.

Some key notes about it,
* no mortar used to bind the stones
* the wall around the enclosure isn't defensive
* had been abandoned for 300+ years by the time Europeans came across it
* the local Africans wouldn't go near it because it's where devils lived
* something like 100 stone houses built in the same manner.

So who the fuck built it? It was supposedly built around 1100 AD. Which is a few hundred years before Europeans and Arabs came to the areas.
Did African natives build it, and then lose all knowledge of construction, reverting back to mud and thatch huts?