Program three in the Lost Kingdoms of Africa series was the weakest so far. That’s partly because Gus Casely-Hayford and his crew were lucky to be allowed into Zimbabwe at all. The BBC is not exactly popular in that part of the world. Also the medieval kingdoms of Southern Africa appear to have left no written records, so we know little about them other than the ruins they left behind and what Portuguese adventurers have written about them. Even so, Wikipedia manages to tell a much more complex story about Zimbabwe than the program did, with reference to two successor kingdoms that Casely-Hayford didn’t mention.

The star of the program, however, was the little island kingdom of Kilwa Kisiwani. Strategically located on the East African coast just where trade ships following the monsoon winds across the Indian Ocean needed it, this little island became a wealthy trading hub exchanging gold from Zimbabwe for spices from Asia.

That picture, which is from the Wikipedia article, shows part of the ruins of the Great Mosque on the island. It is of similar antiquity to Notre Dame in Paris, and also similarly impressive. But stone was in short supply on the island, so the original structure was built entirely of coral.