Queen Mother Pendant Mask
When I was in elementary school my uncle gave me a world history book, and the image of this mask is one of the things that I remembered from that book, probably because I found it creepy. I've seen a picture of this again in my humanities textbook when I was in college, but I could not remember finding out what it was.
The ivory mask was from the Kingdom of Benin (present day Nigeria). Dated to about 16th century AD, the mask was created for the king, Oba Esigie, in honor of his mother, Idia. Ivory was the primary commodity of the kingdom, which attracted the Portugese, and later the British, which conquered the city.
An identical mask is on display at the British Museum.