Four-part series in which British art historian Dr Gus Casely-Hayford explores the pre-colonial history of some of Africa's most important kingdoms. The African continent is home to nearly a billion people. It has an incredible diversity of communities and cultures, yet we know less of its history than almost anywhere else on earth. But that is beginning to change. In the last few decades, researchers and archaeologists have begun to uncover a range of histories as impressive and extraordinary as anywhere else in the world. The series reveals that Africa's stories are preserved for us in its treasures, statues and ancient buildings - in the culture, art and legends of the people. In 1871, European explorers stumbled across an astonishing ruined city deep in the African interior. Great Zimbabwe has been a source of fascination and controversy ever since, a symbol of African genius and a fascinating insight into the empires which once dominated southern Africa. Casely-Hayford goes in search of the roots of this immense kingdom. He traces the trade in gold and precious goods that sustained it and uncovers the kingdoms that grew up around it.