1. Castles.
2. Abelard and Héloïse.
3. The Crusades.
4. The Tale of Genji.
5. Beowulf.
6. Movable type.
7. The law of sines.
8. Paper money.
9. Corgis.
10. Playing cards.
11. Vikings.
12. Oslo, Norway.
13. Silk.
14. The number zero.
15. Porcelain.
