What five features made Benin famous as a centre of ancient civilization?

This was a very unpopular question.  Many of the candidates wasted time either discussing the political structure of Benin kingdom or explaining the factors that promoted the rise of Benin kingdom.  For them to score high marks, they should have explained the following features:
                                                                                           

1. the Benin City wall had a massive earth work;
2. the Benin ivory carvings were used to record historical events;
3. the Benin ivory carvings were also used for decorative purposes;
4. Benin bronze works were among the most beautiful in the world;
5. Benin brass work made Benin famous;
6. decorative woodwork was used to distinguish the buildings of the nobles.