I am fascinated by the beautiful terracotta sculptures of the Nigerian Nok culture, which date back to 500 B.C. These sculptures were unearthed in the first half of the 19th century, in Jos Plateau region of Nigeria. They make one wonder about the society and the people that produced such art. Unfortunately, though, not much is known. But here's a good website that discusses the style and the composition of the sculptures .
Information about the picture to the right is on this Wikipedia page. I got the picture below a while ago from some forum but am unable to trace the source now.